1991 GMC C1500 Motor Oil

Essential 1991 GMC C1500 Motor Oil

Mobil Delvac – 1300 Super Heavy Duty Synthetic Blend Diesel Engine Oil 15W-40, 5 Gallons (Part No.44823)

1300 Super Heavy Duty Synthetic Blend Diesel Engine Oil 15W-40, 5 Gallons

from

$108.99
Mobil Delvac 1300 Super 15W-40 is a high-performance synthetic blend diesel engine oil that helps to extend engine life for diesel vehicles and equipment used in on and off-highway applications. Mobil Delvac 1300 Super is developed in collaboration with top OEMs (original equipment manufacturers) and is recommended for a wide range of heavy-duty applications like the trucking, mining, construction, agricultural, and marine industries. This engine oil helps to deliver extended performance for up to 50% beyond OEM recommended oil drain intervals. (1) Mobil Delvac 1300 Super 15W-40 is a fully backward-compatible oil that works to deliver excellent soot and viscosity control. Mobil Delvac 1300 Super diesel engine oil has outstanding resistance to oil consumption as well as resistance to corrosive and abrasive wear. For nearly a century, Mobil Delvac is the diesel engine oil of choice for the world’s leading heavy-duty original equipment manufacturers (OEMs) (2) and helps protect your engine to keep you going strong on the road. Formulated to meet or exceed the requirements of API CH-4, CI-4, CI-4 PLUS, CJ-4, CK-4, SN, JASO DH-2-17, ACEA E7, ACEA E9, Caterpillar ECF-3, Cummins CES 20086, and Isuzu DEO (with DPD Equipped Vehicles). Approved by the following OEMs: Deutz DQC II-10 LA, Detroit Fluids Specification 93K218, Detroit Fluids Specification 93K222, Mack EOS-4.5, Mack EO-O Premium Plus, MB-Approval 228.31, Renault Trucks RLD-3, MAN M 3575, MAN M 3275-1, Volvo VDS-4, Volvo VDS-4.5. ( (1) Results may vary based on vehicle/engine condition, driving, and environmental conditions. Consult OEM or ExxonMobil before implementing extended ODIs. (2) Compared to a SAE 15W-40 conventional engine oil. Savings are dependent on vehicle engine type, outside temperature, driving conditions, and your current engine oil viscosity.)

Product Features:
  • Mobil Delvac 1300 Super 15W-40 is a premium synthetic blend diesel engine oil that helps extend engine life for diesel vehicles and equipment.
  • Developed with top Original Equipment Manufacturers for a wide range of heavy-duty applications and environments
  • Helps to deliver extended performance for up to 50% beyond OEM-recommended oil drain intervals (1)
  • Fully backward-compatible to deliver exceptional performance in newer and older heavy-duty engines, as well as gasoline engines with API SN specifications
  • Provides excellent soot and viscosity control as well as resistance to oil consumption and corrosive wear
  • Manufacturer Part Number: 121605
See More

Castrol – EDGE 10W-30 Advanced Full Synthetic Motor Oil, 5 Quarts (Part No.1598B6)

EDGE 10W-30 Advanced Full Synthetic Motor Oil, 5 Quarts

from

$37.99
Castrol EDGE 10W-30 is an advanced full synthetic motor oil and the optimal choice for drivers who want the best combination of wear protection, viscosity control and thermal stability to maximize engine performance. It is one of Castrols strongest engine oils with the strength to maintain this unsurpassed level of engine protection for up to 20,000 miles between oil changes or one year.

Product Features:
  • 3X Stronger than the leading full synthetic (1)
  • 10X Better high stress performance (2)
  • 20,000 miles between oil changes (3)
  • (1) Viscosity breakdown as measured in Kurt Orbahn test on 5W-30 grade
  • (2) As measured in Seq IX test under high load/torque conditions vs. API SP test limits
  • (3) Or one year, whichever comes first
  • Approved and Licensed Specifications:
  • Exceeds API SP/SN PLUS/SN/SM
See More

FRAM – 10W-30 Small Engine 10W-30 Conventional Oil: 1 Quart (Part No.464-32)

10W-30 Small Engine 10W-30 Conventional Oil: 1 Quart

from

$7.29
10W-30 Small Engine 10W-30 Conventional Oil: 1 Quart

Valvoline – High Mileage with MaxLife Technology Synthetic Blend 10W-30 Engine Oil: Maximize Engine Life, 5 Quart (Part No.881161)

High Mileage with MaxLife Technology Synthetic Blend 10W-30 Engine Oil: Maximize Engine Life, 5 Quart

from

$29.99
75,000 miles is more than a mile marker. It’s a signal that your engine is ready for greater protection. That’s when you need Valvoline High Mileage with MaxLife Technology Motor Oil. Its exclusive formula is proven to maximize engine life in cars, trucks, and SUVs with over 75,000 miles. Our mixture is specially developed with a unique combination of synthetic and premium conventional oils to protect your high-mileage motor against wear, friction, heat, and deposits – the four major causes of engine breakdown and expensive repairs. Anti-wear additives defend critical engine components, advanced friction-fighting agents reduce heat and abrasion, added detergents clean the inside of your engine, and premium seal conditioners handle aging seals to prevent leaks. It fights sludge, corrosion and rust that can rob your engine of horsepower, fuel efficiency and longevity. From extreme temperatures and cold starts to stop-and-go traffic and frequent short trips, viscosity modifiers make sure the oil flows more easily, coats more completely, and resists thermal breakdown under even the most intense driving conditions. Its unique mixture curbs contaminants to keep high-mileage engines from burning and consuming oil that can foul spark plugs, creating higher emissions and causing your motor to run roughly.

Product Features:
  • Maxlife technology prevents engine breakdown with 40% better wear protection than the industry standard
  • Refresh aging seals and prevent leaks with seal conditioners
  • Reduce sludge, deposits, corrosion, and rust with added detergents – keep motors clean inside
  • Enhanced friction performance helps maximize power with advanced friction-fighting agents
  • Meets or exceeds all requirements of ilsac gf-6a, api sp, api sn with sn plus, api sn
  • MaxLife Technology: The exclusive formula of Valvoline High Mileage with MaxLife Technology Engine Oil is proven to maximize engine life in cars, trucks, and SUVs with over 75,000 miles.
See More

FRAM – 5 Qt Engine Oil High Milage Conventional 5W30 Restores Seals to Reduce Oil Consumption (Part No.F660-5QT)

5 Qt Engine Oil High Milage Conventional 5W30 Restores Seals to Reduce Oil Consumption

from

$25.99
FRAM Conventional High Mileage 5W30 Engine Oil is specially designed with enhanced  additives to help reduce leaks and oil consumption in worn or higher mileage engines. This oil is formulated to help clean out sludge buildup and keep engines running clean and with  increased efficiency and power. They are specially designed for engines with over 75,000 miles.  FRAM Conventional High Mileage 5W30 Engine Oil will protect domestic and imported vehicles and  equipment powered with either gasoline or light duty diesel engines – even those that are turbo charged or super-charged. This high-quality oil is specifically formulated to meet or exceed  all new car manufacturers’ warranty requirements as well as the stringent industry standards API  SP/CF, and 5W30 grades will also meet or exceed the ILSAC GF-6A Resource Conserving Service Category.

Product Features:
  • Formulated with a unique combination of premium base oils and an enhanced additive system
  • Provides increased protection in higher mileage engines
  • Helps restore seal condition to reduce oil consumption
  • Increases protection against high temperature deposits and ring sticking
  • Always refer to your vehicles operating manual to select the correct grade oil for your engine.
  • Specially formulated for engines with over 75,000 miles to help reduce leaks and oil consumption.
See More

Shell – T4 Triple Protection 15W-40 Conventional Heavy Duty Diesel Motor Oil, 1 Gallon (Part No.550045126)

T4 Triple Protection 15W-40 Conventional Heavy Duty Diesel Motor Oil, 1 Gallon

from

$25.99
Improved technology. Same hard work Shell Rotella T4 Triple Protection Heavy Duty Engine Oil builds upon the heritage of Triple Protection you have come to depend on. Today, it’s more advanced than ever, designed to provide hard working protection that adapts to driving conditions.

Product Features:
  • Enhanced protection against oxidation
  • Enhanced wear protection
  • Improved deposit control/cleanliness
  • Sustained emission control system durability in particulate filters and after-treatment systems. (Compared to prior Shell Rotella Triple Protection 15W-40.)
  • Provides enhanced protection against oil oxidation for more efficient operation
See More

Mobil Delvac – Extreme 15W-40 Synthetic Heavy Duty Diesel Engine Oil 1 Gallon (Part No.11635)

Extreme 15W-40 Synthetic Heavy Duty Diesel Engine Oil 1 Gallon

from

$28.99
Mobil Delvac Extreme 15W-40 is a high-performance synthetic diesel engine oil that helps to deliver extended performance for up to two times beyond OEM recommended oil drain intervals (1) for modern diesel engines operating in extreme conditions. Mobil Delvac Extreme 15W-40 is recommended for use in a wide range of heavy-duty applications and operating environments found on- and off-highway conditions, including engines operating under heavy loads. Fully backward compatible, it delivers excellent performance in both newer and older heavy-duty engines, meeting or exceeding the requirements of API CK-4, CJ-4, CI-4 PLUS, CI-4, and other service categories. This diesel engine oil provides exceptional high temperature performance, oxidation stability (2), and resistance to corrosive and abrasive wear to help promote long life of critical wear surfaces. Mobil Delvac Extreme 15W-40 also offers excellent low-temperature performance for increased oil flow to critical bearing surfaces at startup, controlling fluidity and pumpability for smooth starting in cold weather. ( (1)Results may vary based on vehicle/engine condition, driving and environmental conditions Consult OEM or ExxonMobil before implementing extended ODIs. (2) Based on the performance in the Volvo T-13 engine test.)

Product Features:
  • Manufacturer Part Number: 122448
See More

Pennzoil – Platinum 5W-30 Full Synthetic Motor Oil, 1 Quart (Part No.550022689)

Platinum 5W-30 Full Synthetic Motor Oil, 1 Quart

from

$11.49
Pennzoil Platinum full synthetic SAE 5W-30 motor oil is uniquely engineered from our revolutionary PurePlus gas-to-liquid technology, which is a patented process that converts pure natural gas into a high quality, full synthetic base oil. Our high quality base oil is 99.5% pure, contains fewer impurities than base oils made from crude oil, and when combined with our advanced additive technology creates one of the best formulations in our Pennzoil portfolio. Pennzoil Platinum full synthetic SAE 5W-30 motor oil is licensed and meets the vehicle warranty requirements of GM’s dexos 1 Gen 2 specifications that are set forth to meet today’s modern engine technologies. This means that our Pennzoil Platinum full synthetic products meet the stringent requirements of leading car manufacturers. Why does this matter? Modern engine technologies have evolved over the years and today’s engine parts have reached an unprecedented level of fine manufacturing tolerances which require a high-quality engine oil to help provide complete engine protection. This includes protection against abnormal combustion phenomenon like low-speed pre-ignition observed in modern turbocharged gasoline direct injection (TGDI) engines.

Product Features:
  • Provides better fuel economy-drive on average an extra 550 miles per year (versus a dirty engine)
  • Pennzoil Platinum 5W-30 keeps pistons up to 45% cleaner than the toughest industry standard (Based on Sequence IIIH results)
  • No other leading synthetic oil provides better wear protection from friction (Based on Sequence IVA wear test using SAE 5W-30)
  • Formulated to provide faster low-temperature oil flow and protection in extreme heat
  • Helps protect engines from loss of power
  • Formulated for modern turbocharged engines-GF-6, API SP/SP-Resource Conserving and all previous categories
  • Revolutionary PurePlus Technology: Engineered from Pennzoil’s patented PurePlus gas-to-liquid technology, converting pure natural gas into high-quality, full synthetic base oil.
  • High Purity Base Oil: Contains 99.5% pure base oil with fewer impurities compared to oils made from crude oil, ensuring superior engine performance and protection.
  • Advanced Additive Technology: Combines high-quality base oil with advanced additives to create one of the best formulations in the Pennzoil portfolio.
  • Meets GM’s dexos 1 Gen 2 Specifications: Licensed and meets the vehicle warranty requirements of GM’s dexos 1 Gen 2 specifications, suitable for modern engine technologies.
See More

Castrol – EDGE 10W-30 Advanced Full Synthetic Motor Oil, 1 Quart (Part No.152E4E)

EDGE 10W-30 Advanced Full Synthetic Motor Oil, 1 Quart

from

$11.99
Castrol EDGE 10W-30 is an advanced full synthetic motor oil and the optimal choice for drivers who want the best combination of wear protection, viscosity control and thermal stability to maximize engine performance. It is one of Castrols strongest engine oils with the strength to maintain this unsurpassed level of engine protection for up to 20,000 miles between oil changes or one year.

Product Features:
  • 3X Stronger than the leading full synthetic (1)
  • 10X Better high stress performance (2)
  • 20,000 miles between oil changes (3)
  • (1) Viscosity breakdown as measured in Kurt Orbahn test on 5W-30 grade
  • (2) As measured in Seq IX test under high load/torque conditions vs. API SP test limits
  • (3) Or one year, whichever comes first
  • Approved and Licensed Specifications:
  • Exceeds API SP/SN PLUS/SN/SM
  • ILSAC GF-6
See More

Mobil 1 – Truck & SUV 5W-30 Full Synthetic Motor Oil, 1 Quart (Part No.14988)

Truck & SUV 5W-30 Full Synthetic Motor Oil, 1 Quart

from

$11.99
You count on your gas-powered truck or SUV for more than just transportation. For a motor oil that works as hard as you do, you can trust Mobil 1 Truck & SUV full-synthetic motor oil 5W-30. Mobil 1 Truck & SUV utilizes Mobil 1’s signature Triple Action Formula to deliver outstanding engine protection and cleanliness to your engine for up to 10,000 miles between oil changes, (1) and proven performance in a 10,000 lb. towing test. (2) Mobil 1 Truck & SUV full-synthetic motor oil 5W-30 is also 10% more resistant to oil breakdown (3) and meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping your fuel economy. Mobil 1 is America’s No. 1 selling synthetic motor oil brand at retail, (4) trusted recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR. ( (1) Protects for up to 10,000 miles or 1 year, whichever comes first. To learn more about the Mobil 1 Limited Warranty, visit Mobil.US. (2) Please reference your vehicle owner’s manual for information on your engine’s maximum towing / hauling capacity. (3) Versus leading synthetic competitors in proprietary oxidation test. (4) Source: The NPD Group/ Retail Tracking Service/ Dollar Sales/ PCMO full-synthetic/ 52 weeks ending July 1, 2023)

Product Features:
  • Mobil 1 Truck & SUV advanced full-synthetic motor oil 5W-30 is specially formulated for hardworking trucks and SUVs that operate in tough conditions like towing and hauling.
  • Helps protect critical engine parts for up to 10,000 miles between oil changes,(1) controlling oxidation to prevent oil breakdown and maintaining excellent viscosity
  • Utilizes Mobil 1’s signature Triple Action Formula to deliver outstanding engine protection, cleanliness, and proven performance in a 10,000 lb. towing test(2)
  • Additives that help prevent deposit formation
  • Provides excellent internal engine heat protection (up to 500 degrees F) and low temperature protection (to -40 degrees F)
  • Keeps your engine running like new by providing unsurpassed wear protection
  • Manufacturer Part Number: 124599
  • Superior Oil Breakdown Resistance: This motor oil is 10% more resistant to oil breakdown compared to leading synthetic competitors, ensuring longer-lasting engine protection.
  • Meets ILSAC GF-6 Standards: Mobil 1 Truck & SUV full-synthetic motor oil 5W-30 meets ILSAC GF-6 standards, providing low-speed pre-ignition (LSPI) and timing chain wear protection while helping to improve fuel economy.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR«.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR®.
See More

Castrol – GTX 5W-30 Synthetic Blend Motor Oil, 5 Quart (Part No.15A66D)

GTX  5W-30 Synthetic Blend Motor Oil, 5 Quart

from

$29.99
Castrol GTX 5W-30 is a synthetic blend motor oil with a double-action formula proven to clean away the sludge that can block engine oilways (1) and help prevent new sludge formation. Sludge is a thick, tar like substance caused by severe driving conditions such as heavy traffic, poor fuel quality, harsh driving conditions and exceeding oil change intervals. Sludge can block your engine’s vital oilways like cholesterol and if untreated, can rob an engine of its power and ultimately its life. (1) When tested in engines with a high level of sludge.

Product Features:
  • Premium-quality base oils and anti-wear additives that help extend engine life
  • Superior protection against engine sludge
  • Advanced protection against viscosity and thermal breakdown
  • Superior protection against high-temperature deposits
  • Meets or exceeds the following specifications:
  • API SP/SN PLUS/SN/SM
  • ILSAC GF-6
  • ILSAC GF-6
  • Meets Ford WSS-M2C946-B1
See More

Castrol – EDGE High Mileage 5W-30 Advanced Full Synthetic Motor Oil, 1 Quart (Part No.15979F)

EDGE High Mileage 5W-30 Advanced Full Synthetic Motor Oil, 1 Quart

from

$12.99
Castrol EDGE High Mileage 5W-30 is an advanced full synthetic motor oil that is specifically designed for vehicles with over 75,000 miles. It’s been engineered to reduce leaks, burnoff and power robbing deposits, but also contains a proprietary additive to protect the emission system. Our Phosphorus Replacement Technology reduces harmful phosphorus to protect the catalytic converter and extend maximum performance. It is the natural choice for drivers who demand maximum performance from their high mileage car.

Product Features:
  • Phosphorus Replacement Technology to help extend the life of the emission system
  • Reduces leaks, oil burnoff and power robbing deposits
  • 15,000 miles between oil changes (1)
  • (1) Or one year, whichever comes first
  • Meets or exceeds the following specifications:
  • API SP/SN PLUS/SN/SM
  • ILSAC GF-6
  • Meets Ford WSS-M2C960-A1
  • Meets engine test requirements of Chrysler MS 6395
  • Meets Ford WSS-M2C946-B1
  • Meets Ford WSS-M2C961-A1
See More

FRAM – 15W40 Conventional Heavy Duty Diesel Engine Oil, 1 Gallon (Part No.F645-1G)

15W40 Conventional Heavy Duty Diesel Engine Oil, 1 Gallon

from

$19.99
FRAM Heavy Duty 15W-40 Diesel Oil is premium high performance diesel engine oil utilizing the latest in engine oil additive technology to offer the ultimate protection of your engine. Designed to meet or exceed the latest OEM and API CK-4 requirements, it is also backwards compatible to previous OEM and API specifications such as CJ-4, CI-4, CI-4+, and CH-4. STP 15W-40 Diesel Oil carries the API SN classification for use in gasoline engines and is an excellent choice for operators with mixed fleets. The FRAM HD 15W-40 diesel oil is specially designed to protect EGR/Low-Emission Diesel Engines while maximizing the durability of Diesel Particulate Filters (DPF’s).

Product Features:
  • High soot handling
  • Improved sludge control
  • Excellent component protection for corrosion and wear
  • Superior oxidation stability
  • Shear stable formulation
  • One oil for mixed Fleets
  • Exceptional oil consumption control.
  • ALWAYS REFER TO YOUR VEHICLES OPERATING MANUAL TO SELECT THE CORRECT GRADE OIL FOR YOUR ENGINE.
See More

Mobil 1 – Advanced Full Synthetic Engine Oil 10W-30 – 5 Quart (Part No.44898)

Advanced Full Synthetic Engine Oil 10W-30 - 5 Quart

from

$37.99
Mobil 1 advanced full synthetic motor oil 10W-30 helps to extend engine life for vehicles of all ages. Mobil 1 advanced synthetic motor oil is designed to deliver outstanding engine protection from the five factors that can damage engines over time and protect critical engine parts for up to 10,000 miles between oil changes (1). Its uniform synthetic oil molecules reduce friction, helping to prevent deposits and sludge buildup. Mobil 1 helps to keep your engine running at lower temperatures (2). This technologically advanced motor oil is proven to cool engine temperatures by over 10% (3). Its formulation provides excellent internal engine heat protection (up to 500 degrees Fahrenheit), and low-temperature protection (to -30 degrees Fahrenheit), supporting quick cold-weather starting and ultra-fast protection. Mobil 1 advanced full synthetic motor oil meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy. Mobil 1 advanced full synthetic motor oil 10W-30 also helps control oxidation to prevent oil breakdown and is recommended by ExxonMobil for all types of modern vehicles, including high-performance turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines found in passenger cars, SUVs, light vans, and light trucks. Mobil 1 is Americas leading synthetic motor oil brand at retail(4), recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR. ((1) Protects for up to 10,000 miles or 1 year, whichever comes first. To learn more about the Mobil 1 Limited Warranty, visit Mobil.US. (2) Compared to conventional oil. (3) Based on proprietary engine testing, results may vary. (4) Source: The NPD Group/Retail Tracking Service/Dollar Sales/PCMO Full Synthetic/52 weeks ending July 1, 2023.)

Product Features:
  • Mobil 1 advanced full-synthetic engine oil 10w-30 utilizes Mobil 1’s signature triple action formula to deliver outstanding engine performance, protection, and cleanliness.
  • Helps protect critical engine parts for up to 10,000 miles between oil changes,(1) controlling oxidation to prevent oil breakdown and maintaining excellent viscosity
  • Meets ilsac gf-6 standards to help provide low-speed pre-ignition (lspi) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy
  • Mobil 1 is specially formulated to help remove sludge and lower engine temperatures
  • Provides excellent internal engine heat protection (up to 500 degrees f) and low temperature protection (to -30 degrees f)
  • Manufacturer part number: 122326
See More

Castrol – GTX High Mileage 5W-30 Synthetic Blend Motor Oil, 1 Quart (Part No.149D6A)

GTX High Mileage 5W-30 Synthetic Blend Motor Oil, 1 Quart

from

$10.49
Castrol GTX High Mileage 5W-30 is the #1 consumer high-mileage brand of motor oil. It’s a synthetic blend engine oil that helps extend the life of engines by protecting against sludge, wear and burn-off. Engineered with Phosphorous Replacement Technology, it also protects emission systems by replacing some of the phosphorous that can damage catalytic converters.

Product Features:
  • Phosphorus Replacement Technology helps extend emission system life
  • Superior dispersancy that fights sludge build up
  • Exceptional oil burn-off protection exceeding industry standards (1)
  • Seal conditioners to help reduce leaks
  • Advanced additives that minimize engine wear
  • Improved fuel economy (2)
  • (1)Based on API and ACEA volatility specifications
  • Approved for BMW M-Models
  • (2) In 5W-20, 5W-30 and 10W-30 grades versus industry specifications
  • Meets or exceeds the following specifications:
  • API SP/SN PLUS/SN/SM
  • ILSAC GF-6
  • Meets Ford WSS-M2C946-B1
  • Meets Ford WSS-M2C961-A1
See More

Valvoline – High Mileage with MaxLife Technology Synthetic Blend 10W-30 Motor Oil: Maximize Engine Life, 5 Quart (Part No.779462)

High Mileage with MaxLife Technology Synthetic Blend 10W-30 Motor Oil: Maximize Engine Life, 5 Quart

from

$31.99
75,000 miles is more than a mile marker. It’s a signal that your engine is ready for greater protection. That’s when you need Valvoline High Mileage with MaxLife Technology Motor Oil. Its exclusive formula is proven to maximize engine life in cars, trucks, and SUVs with over 75,000 miles. Our mixture is specially developed with a unique combination of synthetic and premium conventional oils to protect your high-mileage motor against wear, friction, heat, and deposits – the four major causes of engine breakdown and expensive repairs. Anti-wear additives defend critical engine components, advanced friction-fighting agents reduce heat and abrasion, added detergents clean the inside of your engine, and premium seal conditioners handle aging seals to prevent leaks. It fights sludge, corrosion and rust that can rob your engine of horsepower, fuel efficiency and longevity. From extreme temperatures and cold starts to stop-and-go traffic and frequent short trips, viscosity modifiers make sure the oil flows more easily, coats more completely, and resists thermal breakdown under even the most intense driving conditions. Its unique mixture curbs contaminants to keep high-mileage engines from burning and consuming oil that can foul spark plugs, creating higher emissions and causing your motor to run roughly.

Product Features:
  • MAXLIFE TECHNOLOGY PREVENTS engine breakdown with 40% better wear protection than the industry standard
  • REFRESH AGING SEALS AND PREVENT LEAKS with seal conditioners
  • REDUCE SLUDGE, DEPOSITS, CORROSION, AND RUST with added detergents – keep motors clean inside
  • ENHANCED FRICTION PERFORMANCE HELPS MAXIMIZE POWER with advanced friction-fighting agents
  • MEETS OR EXCEEDS ALL REQUIREMENTS of ILSAC GF-6A, API SP, API SN with SN PLUS, API SN
  • MaxLife Technology: Valvoline High Mileage with MaxLife Technology is specially formulated to maximize engine life in vehicles with over 75,000 miles, providing superior protection against wear, friction, heat, and deposits.
  • Synthetic Blend Composition: This motor oil features a unique combination of synthetic and premium conventional oils, ensuring optimal performance and protection for high-mileage engines.
See More

Castrol – EDGE 5W-30 Advanced Full Synthetic Engine Oil, 5 Quart (Part No.1598B1)

EDGE 5W-30 Advanced Full Synthetic Engine Oil, 5 Quart

from

$37.99
Castrol EDGE 5W-30 is an advanced full synthetic motor oil and the optimal choice for drivers who want the best combination of wear protection, viscosity control and thermal stability to maximize engine performance. It is one of Castrols strongest engine oils with the strength to maintain this unsurpassed level of engine protection for up to 20,000 miles between oil changes or one year.

Product Features:
  • 3X Stronger than the leading full synthetic (1)
  • 10X Better high stress performance (2)
  • 20,000 miles between oil changes (3)
  • (1) Viscosity breakdown as measured in Kurt Orbahn test on 5W-30 grade
  • (2) As measured in Seq IX test under high load/torque conditions vs. API SP test limits
  • (3) Or one year, whichever comes first
  • Approved and Licensed Specifications:
  • ILSAC GF-6
  • Exceeds API SP/SN PLUS/SN/SM
  • GM dexos1 Gen 3
  • Meets engine test requirements of Chrysler MS 6395
  • Meets Ford WSS-M2C946-B1
  • Meets Ford WSS-M2C961-A1
See More

Mobil Super – 5W-30 Synthetic Blend Motor Oil, 5 Quart (Part No.98010)

5W-30 Synthetic Blend Motor Oil, 5 Quart

from

$25.99
Mobil 1 advanced full synthetic motor oil 5W-30 helps to extend engine life for vehicles of all ages. Mobil 1 advanced synthetic motor oil is designed to deliver outstanding engine protection from the five factors that can damage engines over time and protect critical engine parts for up to 10,000 miles between oil changes. Its uniform synthetic oil molecules reduce friction, helping to prevent deposits and sludge buildup. This technologically advanced motor oil formulation provides excellent internal engine heat protection (up to 500 degrees Fahrenheit), and low-temperature protection (to -30 degrees Fahrenheit), supporting quick cold-weather starting and ultra-fast protection. Mobil 1 advanced full synthetic motor oil meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy. Available in 1-qt. and 5-qt. bottles, Mobil 1 advanced full synthetic motor oil 5W-30 also helps control oxidation to prevent oil breakdown and is recommended by ExxonMobil for all types of modern vehicles, including high-performance turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines found in passenger cars, SUVs, light vans, and light trucks. Mobil 1 is America’s leading synthetic motor oil brand at retail, recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR®. (Protects for up to 10,000 miles or 1 year, whichever comes first. To learn more about the Mobil 1 Limited Warranty, visit Mobil.US. Source: The NPD Group/ Retail Tracking Service/ Dollar Sales/ 52 weeks ending January 2, 2021)

Product Features:
  • Mobil 1 advanced full synthetic motor oil 5W-30 helps to protect your engine from the five factors that can damage engines over time
  • Helps to protect critical engine parts for up to 10,000 miles between oil changes, controlling oxidation to prevent oil breakdown and maintaining excellent viscosity
  • Meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy
  • Helps extend engine life by working to prevent damaging deposits and sludge buildup
  • Provides excellent internal engine heat protection (up to 500 degrees F) and low temperature protection (to -30 degrees F)
See More

FRAM – 10W-30 High Mileage Full Synthetic Motor Oil: 1 Quart (Part No.F943)

10W-30 High Mileage Full Synthetic Motor Oil: 1 Quart

from

$7.99
FRAM Full Synthetic High Mileage SAE 10W-30 is a full synthetic motor oil blended with high quality synthetic base stocks and and enhanced additives that meet the stringent API: SP, SN, SM, SL, SJ, and ILSAC GF-6A specifications while reducing leaks and oil consumption in worn or higher mileage engines. Formulated with synthetic base stocks, this oil offers increased oxidation inhibition performance as well as increased high and low temperature performance when compared against conventional oils. The FRAM Full Synthetic High Mileage SAE 10W-30 is formulated to help clean out sludge buildup and keep engines running clean and with increased efficiency and power. Specially designed for engines with over 75,000 miles, the FRAM Full Synthetic High Mileage SAE 10W-30 provides the ultimate protection for your higher mileage engine. Specifically formulated for the rigorous environment of gas-direct engine (GDI) and turbo gas-direct engine (TGDI) designs as well as providing increased protection for carbureted or normally fuel injected engines. FRAM Full Synthetic High Mileage SAE 10W-30 contains additive technology designed to prevent low-speed pre-ignition (LSPI). LSPI can lead to pre-mature engine failure and is a major concern of the automotive industry for vehicles employing GDI or TGDI technology. This oil also provides increased wear protection, oxidation and shear stability for higher mileage vehicles over previous oil categories.

Product Features:
  • Faster oil flow at start-up
  • Fuel efficiency gains over heavier grade oils
  • Reduces oil cumsumption
  • Excellent sludge and varnish protection
  • Slows engine leaks
  • Outstanding thermal and oxidation stability
  • Lowers oil vaporization and consumption at extreme conditions
  • Always refer to your vehicles operating manual to select the correct grade oil for your engine.
See More

Mobil 1 – Extended Performance 5W-30 Full Synthetic Motor Oil, 5 Quart (Part No.14977)

Extended Performance 5W-30 Full Synthetic Motor Oil, 5 Quart

from

$41.99
If you trust your vehicle to be there for you, you need to be there for its engine, with Mobil 1 Extended Performance full-synthetic motor oil 5W-30. Our ultimate full-synthetic motor oil meets or exceeds the industry’s toughest standards to help you get the most from your engine for up to 20,000 miles between oil changes, guaranteed.(1) Utilizes Mobil 1’s Triple Action+ Formula to combine outstanding engine performance, protection, and cleanliness with the added benefit of maximized engine power. This cutting-edge formula is recommended by ExxonMobil for all types of modern vehicles, including high-performance, turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines found in passenger cars, SUVs, light vans, and light trucks. Mobil 1 is America’s No. 1 synthetic motor oil brand at retail,(2) trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR®. ((1)Protects for up to 20,000 miles or 1 year, whichever comes first. To learn more about the Mobil 1 Limited Warranty, visit Mobil.US.(2)Source: The NPD Group/Retail Tracking Service/Dollar Sales/PCMO full-synthetic/52 weeks ending Feb 25, 2023)

Product Features:
  • Mobil 1 Extended Performance full-synthetic motor oil 5W-30 helps protect critical engine parts for up to 20,000 miles between oil changes,(1) controlling oxidation to prevent oil breakdown and maintaining excellent viscosity
  • Utilizes Mobil 1’s Triple Action+ Formula to combine outstanding engine performance, protection, and cleanliness with the added benefit of power
  • Meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy
  • Helps extend engine life by working to prevent damaging deposits and sludge buildup
  • Provides excellent internal engine heat protection (up to 500 degrees F) and low temperature protection (to -40 degrees F)
  • Manufacturer Part Number: 120766
  • Versatile Compatibility: Recommended for all types of modern vehicles, including high-performance, turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines in passenger cars, SUVs, light vans, and light trucks.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR«.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR®.
See More

Shell – T5 15W-40 Synthetic Blend Heavy Duty Diesel Motor Oil, 1 Gallon (Part No.550045348)

T5 15W-40 Synthetic Blend Heavy Duty Diesel Motor Oil, 1 Gallon

from

$29.99
Through the use of Shell’s most advanced technology, Shell Rotella T5 15W-40 synthetic blend heavy duty engine oil offers enhanced fuel economy capability of up to 1.5% that can save money in fuel consumption, without compromising engine protection or durability.

Product Features:
  • Better fuel economy
  • Better low temperature flow
  • Formulated to control engine wear, 37% better than the maximum wear requirements in API CK-4 engine wear tests (2)
  • Heavy duty engine oil formulated with synthetic base oil components
  • Delivers improved oxidation performance for increased resistance to breakdown under high temperatures compared to the previous formulation
See More

Mobil 1 – ESP 5W-30 Full Synthetic Motor Oil, Reduces Deposits, 1 Quart (Part No.47112)

ESP 5W-30 Full Synthetic Motor Oil, Reduces Deposits, 1 Quart

from

$11.99
Mobil 1 ESP 5W-30 is an advanced full synthetic oil specially formulated for passenger car diesels that have the latest diesel particulate filters (DPFs) and gasoline catalytic converters (CATs). The proprietary full synthetic motor oil is designed to help deliver outstanding performance and protection in conjunction with potential fuel economy benefits. Mobil 1 ESP has active cleaning agents that help to reduce deposits and sludge buildup for a cleaner engine. Helps to reduce oil aging with outstanding oxidation stability for extended drain interval protection. Low ash, sulfur, and phosphorous content help to reduce particulate buildup in DPFs and reduce poisoning of CATs. Excellent low temperature capabilities for quick cold-weather starting and ultra-fast protection. Mobil 1 is America’s leading synthetic motor oil brand at retail(1), recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR. ((1)Source: The NPD Group/ Retail Tracking Service/ Dollar Sales/ PCMO Full Synthetic/ 52 weeks ending July 1, 2023)

Product Features:
  • Mobil 1 ESP 5W-30 full synthetic oil is formulated for passenger car diesels with diesel particulate filters (DPFs) and gasoline catalytic converters (CATs)
  • Low ash, sulfur, and phosphorous content help to reduce particulate build up in DPFs
  • Active cleaning agents that help to reduce deposits and sludge buildup for a cleaner engine
  • Helps to reduce oil aging with outstanding oxidation stability for extended drain interval protection
  • Excellent low temperature capabilities for quick cold-weather starting and ultra-fast protection
  • Manufacturer Part Number: 127568
  • Outstanding Performance and Protection: Designed to deliver exceptional performance and protection, with potential fuel economy benefits.
See More

Castrol – GTX High Mileage 10W-30 Synthetic Blend Motor Oil, 1 Quart (Part No.149D6C)

GTX High Mileage 10W-30 Synthetic Blend Motor Oil, 1 Quart

from

$10.49
Castrol GTX High Mileage 10W-30 is the No. 1 consumer high-mileage brand of motor oil. It’s a synthetic blend engine oil that helps extend the life of engines by protecting against sludge, wear and burn-off. Engineered with Phosphorous Replacement Technology, it also protects emission systems by replacing some of the phosphorous that can damage catalytic converters.

Product Features:
  • Phosphorus Replacement Technology to help extend the life of the emission system
  • Superior dispersancy that fights sludge build up
  • Exceptional oil burn-off protection exceeding industry standards (1)
  • Seal conditioners to help reduce leaks
  • Advanced additives that minimize engine wear
  • Improved fuel economy (2)
  • (1) Based on API and ACEA volatility specifications
  • Meets or exceeds the following specifications:
  • (2) In 5W-20, 5W-30 and 10W-30 grades versus industry specifications
  • Meets or exceeds the following specifications:
  • API SP/SN PLUS/SM
  • ILSAC GF-6
See More

FRAM – Full Synthetic High Mileage 10W-30 Motor Oil: 5 Quart (Part No.F943-5QT)

Full Synthetic High Mileage 10W-30 Motor Oil: 5 Quart

from

$28.99
FRAM Full Synthetic High Mileage SAE 10W-30 is a full synthetic motor oil blended with high quality synthetic base stocks and and enhanced additives that meet the stringent API: SP, SN, SM, SL, SJ, and ILSAC GF-6A specifications while reducing leaks and oil consumption in worn or higher mileage engines. Formulated with synthetic base stocks, this oil offers increased oxidation inhibition performance as well as increased high and low temperature performance when compared against conventional oils. The FRAM Full Synthetic High Mileage SAE 10W-30 is formulated to help clean out sludge buildup and keep engines running clean and with increased efficiency and power. Specially designed for engines with over 75,000 miles, the FRAM Full Synthetic High Mileage SAE 10W-30 provides the ultimate protection for your higher mileage engine. Specifically formulated for the rigorous environment of gas-direct engine (GDI) and turbo gas-direct engine (TGDI) designs as well as providing increased protection for carbureted or normally fuel injected engines. FRAM Full Synthetic High Mileage SAE 10W-30 contains additive technology designed to prevent low-speed pre-ignition (LSPI). LSPI can lead to pre-mature engine failure and is a major concern of the automotive industry for vehicles employing GDI or TGDI technology. This oil also provides increased wear protection, oxidation and shear stability for higher mileage vehicles over previous oil categories.

Product Features:
  • Faster oil flow at start-up
  • Fuel efficiency gains over heavier grade oils
  • Reduces oil cumsumption
  • Excellent sludge and varnish protection
  • Slows engine leaks
  • Outstanding thermal and oxidation stability
  • Lowers oil vaporization and consumption at extreme conditions
  • ALWAYS REFER TO YOUR VEHICLES OPERATING MANUAL TO SELECT THE CORRECT GRADE OIL FOR YOUR ENGINE.
  • Engine Cleaning and Efficiency: Helps clean out sludge buildup, keeping engines running clean with increased efficiency and power, ideal for engines with over 75,000 miles.
  • Advanced LSPI Prevention: Contains additive technology designed to prevent low-speed pre-ignition (LSPI), a major concern for vehicles with gas-direct engine (GDI) and turbo gas-direct engine (TGDI) designs.
  • Comprehensive Engine Protection: Provides increased wear protection, oxidation, and shear stability for higher mileage vehicles, meeting stringent API: SP, SN, SM, SL, SJ, and ILSAC GF-6A specifications.
See More

Mobil Super – 10W-30 Synthetic Blend Motor Oil, 1 Quart (Part No.97025)

10W-30 Synthetic Blend Motor Oil, 1 Quart

from

$5.89
Mobil Super 10W-30 Synthetic Blend motor oil helps to extend your engine life and provide engine protection up to 5,000 miles for gasoline cars and light-duty trucks. Mobil Super has 15 percent extra cleaning additives to help prevent the formation of sludge and deposits when compared to Mobil conventional motor oil. Helps to get your engine cleaner, conserve viscosity for easier cold starting, and provide outstanding engine wear protection under a variety of operating conditions. Meets or exceeds the requirements of: API SN, SM, SL, API SN Plus.

Product Features:
  • Mobil Super Synthetic Blend motor oil 10W-30 works to protect your engine from sludge and deposits for up to 5,000 miles
  • Helps to keep your engine clean with 15 percent extra cleaning additives, preventing sludge and deposit formation
  • Works to provide outstanding engine wear protection under a variety of operating conditions
  • Enhanced formulation (vs. Mobil basic conventional oil) helps to conserves oil viscosity for easier cold starting
  • Recommended for gasoline cars and light-duty trucks
See More

FRAM – 10W-30 Full Synthetic Motor Oil, Ultimate Protection, 5 Quarts (Part No.F940-5QT)

10W-30 Full Synthetic Motor Oil, Ultimate Protection, 5 Quarts

from

$27.99
FRAM Engine Oil Full Synthetic SAE 10W-30 is a full synthetic motor oil blended with high  quality synthetic base stocks and the latest additive technology to provide the ultimate protection  for your engine. Specifically formulated for the rigorous environment of gas-direct engine (GDI)  and turbo gas-direct engine (TGDI) designs as well as providing increased protection for  carbureted or normally fuel injected engines. FRAM Engine Oil Full Synthetic SAE 10W-30  contains additive technology designed to prevent low-speed pre-ignition (LSPI). LSPI can lead  to pre-mature engine failure and is a major concern of the automotive industry for vehicles  employing GDI or TGDI technology. This oil also provides increased wear protection, oxidation  and shear stability over previous oil categories.

Product Features:
  • Outstanding thermal and oxidation stability
  • Excellent sludge and varnish protection
  • Faster oil flow at start-up
  • Volatility: Lowers oil vaporization and consumption at extreme conditions
  • ALWAYS REFER TO YOUR VEHICLES OPERATING MANUAL TO SELECT THE CORRECT GRADE OIL FOR YOUR ENGINE.
  • Ultimate Engine Protection: FRAM Engine Oil Full Synthetic SAE 10W-30 is formulated with high-quality synthetic base stocks and the latest additive technology to provide the ultimate protection for your engine.
  • Advanced LSPI Prevention: Contains additive technology specifically designed to prevent low-speed pre-ignition (LSPI), a major concern for vehicles with gas-direct injection (GDI) and turbo gas-direct injection (TGDI) engines.
  • Enhanced Wear Protection: Offers increased wear protection, ensuring your engine components remain in optimal condition even under rigorous driving conditions.
  • Versatile Engine Compatibility: Suitable for a wide range of engines, including GDI, TGDI, carbureted, and normally fuel-injected engines, making it a versatile choice for various vehicle types.
See More

Mobil 1 – Extended Performance 5W-30 High Mileage Full Synthetic Motor Oil, 5 Quart (Part No.15021)

Extended Performance 5W-30 High Mileage Full Synthetic Motor Oil, 5 Quart

from

$41.99
You trust your car to keep you going, even after 75,000 miles. Mobil 1 Extended Performance High Mileage full-synthetic motor oil 5W-30 gives engines with over 75,000 miles the extra care they need to go the distance. Formulated to help prevent leaks, it helps to protect critical engine parts for up to 20,000 miles between oil changes, guaranteed.(1) Utilizes Mobil 1’s Triple Action+ Formula to combine outstanding engine performance, protection, and cleanliness with the added benefit of maximized engine power. This cutting-edge formula is recommended by ExxonMobil for all types of modern vehicles, including high-performance, turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines found in passenger cars, SUVs, light vans, and light trucks. Mobil 1 is America’s No. 1 synthetic motor oil brand at retail,(2) trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR. ((1)Protects for up to 20,000 miles or 1 year, whichever comes first. To learn more about the Mobil 1 Limited Warranty, visit Mobil.US. (2)Source: The NPD Group/Retail Tracking Service/Dollar Sales/PCMO full-synthetic/52 weeks ending July 1, 2023)

Product Features:
  • Mobil 1 Extended Performance High Mileage full-synthetic motor oil 5W-30 is designed for engines with over 75,000 miles to go up to 20,000 miles between oil changes.(1)
  • Utilizes Mobil 1’s Triple Action+ Formula to combine outstanding engine performance, protection, and cleanliness with the added benefit of power
  • Meets ILSAC GF-6 standards to help provide low-speed pre-ignition (LSPI) and timing chain wear protection while keeping your engine clean and helping to improve your fuel economy
  • Provides excellent internal engine heat protection (up to 500 degrees F) and low temperature protection (to -40 degrees F)
  • Helps extend engine life by working to prevent damaging deposits and sludge buildup
  • Manufacturer Part Number: 123843
  • Versatile Compatibility: Recommended for all types of modern vehicles, including high-performance, turbo-charged, and supercharged gasoline and diesel multi-valve fuel-injected engines found in passenger cars, SUVs, light vans, and light trucks.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR«.
  • Trusted Brand: Mobil 1 is America’s No. 1 synthetic motor oil brand at retail, trusted and recommended by car builders and experienced mechanics, and is the Official Motor Oil of NASCAR®.
See More

FRAM – 5 Qt Conventional 5W30 Engine Oil with Low-Speed Pre-Ignition Control (Part No.F620-5QT)

5 Qt Conventional 5W30 Engine Oil with Low-Speed Pre-Ignition Control

from

$25.99
FRAM Engine Oil SAE 5W-30 utilizes a blend of high-quality conventional and synthetic base stocks coupled with a robust additive system to provide reliable engine protection across a broad range of operating conditions. Specifically formulated for use in modern gas-direct engines (GDI) and turbo gas-direct engines (TGDI) as well as older carbureted or normally fuel injected gasoline engine designs. FRAM Engine Oil SAE 5W-30 contains additive technology designed to prevent low-speed pre-ignition (LSPI) while also providing increased wear protection, oxidation and shear stability over previous oil categories. FRAM Engine Oil SAE 5W-30 meets the requirements for API SP, SN Plus, SN, SM and ILSAC GF-6A, GF-5 and earlier API and ILSAC Service Categories.

Product Features:
  • Low-speed pre-ignition control
  • Chain wear protection
  • Piston cleanliness
  • Turbo-compatibility
  • Always refer to your vehicles operating manual to select the correct grade oil for your engine.
  • Reliable engine protection: FRAM Conventional Oil 5W30 5 QT utilizes a blend of high-quality conventional and synthetic base stocks coupled with a robust additive system to provide reliable engine protection across a broad range of operating conditions.
See More

1991 GMC C1500 Motor Oil

Maybe you’re in the middle of a full rebuild of that 1991 GMC C1500. Maybe you just need a couple of Motor Oil. Either way, Advance Auto Parts has 50 different Motor Oil in our inventory ranging from $5.89 to $74.99. That means you can find the exact parts or products you need to keep that 1991 GMC C1500 running smoothly.

Motor Oil are only as good as their brand. We stock 5 different brands to make sure you have plenty of trusted parts to choose from for your 1991 GMC C1500. Castrol, Mobil Oil, and Fram are just some of the brands we stock. Search for brands you know or compare prices and reviews to help you decide!

We know you’ll find the perfect Motor Oil for your 1991 GMC C1500, but don’t take our word for it – read our customer ratings and reviews and buy with confidence. Out of the 36,648 reviews in this category, some of the top rated parts include Extended Performance 5W-30 Full Synthetic Motor Oil, 5 Quart with 4.9 stars and EDGE 5W-30 Advanced Full Synthetic Motor Oil, 1 Quart with 4.9 stars.

So if you’re in the market for aftermarket Motor Oil to keep your 1991 GMC C1500 rolling for years to come, look no further. Shop online and have your products shipped direct to your door, or pick up at the nearest Advance Auto Parts location today!

Motor Oil Brands To Make Your 1991 GMC C1500 Last

Simple repair, complete replacement, or a full rebuild. No matter the job, your 1991 GMC C1500 demands trusted brand parts and products to keep it running. Many trusted brands of Motor Oil make up Advance Auto Parts’ inventory, and all are ready to help make your C1500 the best it can be. Be sure to browse some of our top Motor Oil brands and parts.

FAQs for 1991 GMC C1500 Motor Oil

What are the most purchased Motor Oil for the 1991 GMC C1500?

Out of 50 Motor Oil for the 1991 GMC C1500, the most popular in our inventory are:

What are the top-rated 1991 GMC C1500 Motor Oil?

Top-rated Motor Oil for your 1991 GMC C1500 based on customer reviews/ratings are:
EDGE 5W-30 Advanced Full Synthetic Motor Oil, 1 Quart
from $11.99
(442)
EDGE 5W-30 Advanced Full Synthetic Motor Oil, 1 Quart
“The best oil for my car.”
GTX  5W-30 Synthetic Blend Motor Oil, 5 Quart
from $29.99
(333)
GTX 5W-30 Synthetic Blend Motor Oil, 5 Quart
“Great sale package with filter.”