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Autolite High Thread Spark Plug: Enhanced Durability & Focused Ignition
4 year warranty
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Product Information
Product Details
Part No. HT15
Warranty Details (4 Year Warranty)
Autolite High Thread Pro plugs are expertly crafted for Ford 3V engines, offering unmatched durability and performance. Featuring a fine-wire platinum center electrode, these plugs deliver focused ignition power and extended service life, while the extra-long special electrode projection ensures optimal combustion efficiency. The ground strap enhances heat transfer, outperforming standard J-gap plugs, and the proprietary design boosts heat management, fouling resistance, and dielectric strength. With threads positioned above the cylinder head seating, these plugs create a compressive seal for improved engine reliability. The nickel-plated shell provides superior corrosion resistance, ensuring long-lasting performance even in demanding conditions. Designed and engineered in the USA, these spark plugs embody over a century of Autolite's expertise, making them a premium choice for performance-grade ignition systems.
Product Features:
Product Features:
- Engineered with a fine-wire platinum design that provides more focused ignition power and longer service life.
- The ground strap provides improved heat transfer over standard J-gap plugs.
- Its proprietary design improves performance for heat management, fouling resistance & increased dielectric strength.
- The position of the thread above the cylinder head seating allows for a more compressive seal.
- Designed with a nickel-plated shell that delivers increased protection against corrosion.
- Engineered in the USA: Designed and engineered in the USA, leveraging over 100 years of Autolite's engineering expertise and experience.
Specifications
Center Electrode Core Material:
Copper
Center Electrode Design:
Fine Wire
Center Electrode Projection:
Extra-Long Special
Center Electrode Tip Material:
Platinum
Electrical Terminal Type:
Non-Removable Nut
Electrode Tip Material:
Platinum
Grade Type:
Performance
Ground Electrode Core Material:
Nickel
Ground Electrode Quantity:
1
Ground Electrode Tip Design:
Standard
Ground Electrode Tip Material:
Nickel
Hex Size:
5/8 in
Hex Type:
Hex
Indexed:
No
Insulator Material:
Ceramic
Manufacturer Heat Range:
11
Pre-Gap Size:
0.045 in
Reach:
0.702 in
Resistor:
Suppressor
Resistor Type:
Yes
Seat Type:
Tapered
Skirt:
Yes
Thread Diameter:
16 mm
Tip Configuration:
Power
Washer(s) Included:
No
Wrench Diameter:
9/16 in
4.4 out of 5
35 Customer Reviews
69% of respondents would recommend this to a friend
Ratings Distribution
5 Stars
25
4 Stars
6
3 Stars
0
2 Stars
1
1 Star
3
Pros
3
Easy To Install
3
Improves Engine Efficiency
3
Increases Power
1
Durable
1
None
Cons
1
Difficult To Install
1
Engine Shakes
1
No Power
1
Rough Idle Stalls
Best Uses
3
Everyday Driving
3
Replacement
1
Paper weight
Describe Yourself
3
Mechanic
3
Truck Enthusiast
2
Auto Enthusiast
2
Casual Driver
1
30 Years Experience
Most Liked Positive Review
Clean before removal
Run injector cleaner through gas before removing plugs to remove carbon build-up from around plug. This will prevent end of plug from breaking off on removal. It is very common for these plugs to break off in the cylinder head when carbon encases the end of the plug. I have had 100% success on removal after using carburetor/ injector cleaner for several tanks and have had 100% failure just trying to remove the plug on engines that have over 100,000 miles. Not sure how many tanks are actually required but 2-3 did the job. Have also see this plug design tick like a bad valve. [$] spark plug is much cheaper than a $2500 head job.
Most Liked Negative Review
Just Replaced After 43K
It seemed like it was time for plugs again as my truck started to run rough/misfire every once in a while. All of these plugs came out with no problems(bonus) but all of them have pretty bad carbon tracking. One was loose in the hole(not the plugs fault) but the seat was cracked(maybe plugs fault). I replaced these with Motorcraft and I suggest you do the same. Truck runs like a top.
Reviewed by 35 Customers
Clean before removal
Staff Reviewer -
Run injector cleaner through gas before removing plugs to remove carbon build-up from around plug. This will prevent end of plug from breaking off on removal. It is very common for these plugs to break off in the cylinder head when carbon encases the end of the plug. I have had 100% success on removal after using carburetor/ injector cleaner for several tanks and have had 100% failure just trying to remove the plug on engines that have over 100,000 miles. Not sure how many tanks are actually required but 2-3 did the job. Have also see this plug design tick like a bad valve. [$] spark plug is much cheaper than a $2500 head job.
Bottom Line Yes, I would recommend to a friend
WORST PLUG I HAVE EVER USED!
Staff Reviewer -
Installed this plug during routine tune up. Engine would not idle and ran very rough after i installed them. Put new factory OEM Motorcraft plugs back in and it purred like a kitten. The Autolite HT15 plugs are terrible. They look identical to the motorcraft plug but they are definitely NOT. 2006 Ford Expedition with 5.4 engine. Yes I broke off two plugs in process but the Lisle 65600 broken spark plug tool saved me, it worked great. Under no circumstance would I buy the Autolite HT15 again. I returned them and bought the Motorcraft OEM plug.
Bottom Line No, I would not recommend to a friend
Would by again
Staff Reviewer -
Easy to install, time will tell on longevity
Bottom Line Yes, I would recommend to a friend
Suppose to be better than OEM
Staff Reviewer -
Well, before you remove the old ones from your engine, invest in the spark plug removal kit, I did and I broke 5 out of 8 plugs off in the head. Without the kit to remove them you are at the mercy of a mechanic or the dealership. After the old ones were removed the new ones went in good, use the recommended nickel lubricant for next time.
Bottom Line Yes, I would recommend to a friend
HighThread Spark Plug
Staff Reviewer -
Perfect replacement part, just like OEM.
Bottom Line Yes, I would recommend to a friend
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