Fuel Additive (16 oz.)
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Marvel Mystery Oil Fuel Additive (16 oz.)

Part No. MM12R Warranty Details  
Marvel Mystery Oil helps extend engine life by breaking down and removing harmful deposits of sludge and carbon in your engine oil. When regularly added to your fuel, it helps keep spark plugs and fuel injectors free of carbon deposits, resulting in increased fuel economy. Marvel Mystery Oil fortifies motor oil for increased resistance to high temperatures and easier cold-weather starting.
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Container/Package Size:16 oz
Container/Package Type:Plastic Bottle
Diesel Compatible:Yes
Oil Quantity Treated:5 qt
Stops Leaks:Yes
Synthetic Compatible:Yes

REVIEW SNAPSHOT®

by PowerReviews
Marvel Mystery OilFuel Additive (16 oz.)
 
4.6

(based on 8 reviews)

Ratings Distribution

  • 5 Stars

     

    (5)

  • 4 Stars

     

    (3)

  • 3 Stars

     

    (0)

  • 2 Stars

     

    (0)

  • 1 Stars

     

    (0)

100%

of respondents would recommend this to a friend.

Pros

  • Improves vehicle performance (5)
  • Runs clean (4)

Cons

No Cons

Best Uses

  • Regular use (4)
  • Car (3)
    • Reviewer Profile:
    • Casual driver (3), Mechanic (3)

Reviewed by 8 customers

Displaying reviews 1-8

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4.0

good product

By 

from va

Verified Buyer

Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

Good product

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5.0

Excellent

By 

from Freedom, WI

About Me Casual Driver

Pros

  • Improves Vehicle Performance
  • Reduces Wear

Cons

    Best Uses

    • Car
    • Regular Use
    • Truck

    Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

    help improve performance and life of motor

    Comment on this reviewHelp Icon(earn points)

    (4 of 8 customers found this review helpful)

     
    4.0

    Seems to work well for sludging

    Profile Image

    By 

    from Danielsville, PA

    About Me Mechanic

    Ask me a question

    Level 5

    Pros

    • Improves Vehicle Performance
    • Runs Clean

    Cons

      Best Uses

      • Quick Fix

      Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

      I put this in a Jeep with a 3.7L that had sat for 18 months. It seems to have done a fine job of cleaning out some of the varnish and coking present in the engine.

      I added some to the fuel and had no noticible gain or loss, though I had already seafoamed the tank and engine from sitting about 500 miles prior.

      Comment on this reviewHelp Icon(earn points)

      (6 of 10 customers found this review helpful)

       
      5.0

      Use In Every Oil Chane

      Profile Image

      By 

      from Virginia

      About Me Diesel Mechanic, Mechanic

      Level 3

      Pros

      • Add To Fuel
      • Improves Vehicle Performance
      • Inexpensive
      • Runs Clean

      Cons

      • Thins Oil

      Best Uses

      • Regular Use

      Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

      This is not a "Mechanic In A Can" type of product, its a maintenance treatment. Back in the old days when MMO came in a metal can, the label stated to use 4-oz per quart (12%) of engine oil, today it states to use up to 25% of the oil capacity.

      This stuff will clean out crud that does not dissolve in regular oil and can reduce gummed up dragging engine parts (sticktation) like in the TV commercial where a car is pulling a boat anchor.

      Use Marvels Mystery Oil with every oil change, it really makes a difference in how your vehicle operates. My suggestion is to add 4-oz per quart of engine oil -two weeks- before your first oil change. Repeat the same dosage with new oil, this product will dissolve sludge and a low initial dosage will prevent undue problems.

      Added to the fuel tank, MMO adds even more benefit, MMO keeps your injectors happy. Everything in the fuel system remains clean and lubricated. Cheaper than an injector service with repeated use.

      MMO also makes a good cleaner for gear oil applications to dissolve sludge from neglected differentials. Add 4-oz per quart, give it a few months and change the gear oil, you will be amazed at how much cleaner the gears look; best of all, no dissasembly or scrubbing parts in solvent.

      FYI: To get the best price, look for Marvels Mystery Oil in the 32 oz size.

      Comment on this reviewHelp Icon(earn points)

      (42 of 74 customers found this review helpful)

       
      5.0

      Keeps my 1982 VW Diesel Pickup hoppy

      By 

      from Byron, GA

      About Me Casual Driver, Mechanic

      Verified Buyer
      3 or more reviews submitted

      Pros

      • Reduces Wear
      • Runs Clean

      Cons

        Best Uses

        • Regular Use

        Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

        Keeps older injection pump lubricated with ultra-low sulfur diesel fuel.

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        (37 of 74 customers found this review helpful)

         
        5.0

        Slick as a duck in the pond

        By 

        from Gulfport MS

        About Me Casual Driver

        Verified Buyer
        Level 2

        Pros

        • Improves Vehicle Performance

        Cons

          Best Uses

          • Car

          Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

          First time ever using Marvel Mystery oil got it because of buy one get one free . I noticed right away the improvement in the idleing of my Nissan Altima . I put some in the gas tank as well as the crank case . It hasn't been long enough to fully evealuate the product , but so far so good

          Comment on this reviewHelp Icon(earn points)

          (34 of 66 customers found this review helpful)

           
          4.0

          Marvel Mystery Oil Additive

          By 

          from Knoxville, TN

          About Me Auto Enthusiast

          Ask me a question

          Verified Buyer
          Level 2

          Pros

          • Improves Vehicle Performance
          • Runs Clean

          Cons

            Best Uses

            • Car
            • Regular Use
            • Truck

            Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

            I add this from time to time to all my vehicles and also my lawn tractor. It seems to clean the fuel delivery system and keeps the engine running smoothly when routinely treated. I think it also helps keep out the "gumming" problem from carburetors when using the new ethanol fuels.

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            (40 of 74 customers found this review helpful)

             
            5.0

            A proven solution at a reasonable price

            By 

            from Reading, PA

            Comments about Marvel Mystery Oil Fuel Additive (16 oz.):

            Used for many years by seasoned mechanics, I first learned of this product from an experienced airplane mechanic. I was looking for a cure to my tapping hydraulic valves. I drained some oil from my engine and then added this to my oil. Drove my car for a day and problem was cured, never to return. I'm told this additive has many additional uses and I never heard of any problems with using it.

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            Displaying reviews 1-8

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            Do you have questions about this product?(earn points for answers!)

             

            Ask a question, get answers from real customers and in-house experts. For further assistance, please review your support options on our Contact Us page.

            4 Questions | 4 Answers
            Displaying questions 1-4
            • Q:

              Anny possibility that this product could help me pass smog on my 1997 dodge stratus? I plan to also get an oil change and wondered if this could also be beneficial?
              Asked on 8/1/2013 by Gina from Vacaville,CA

              1 answer

              • CUSTOMER CARE

                A:

                The Marvel Mystery Oil Fuel Additive, 16oz. (Part No. MM12R) is safe for catalytic converters and oxygen sensors. Added to gas it cleans and lubricates fuel injectors and carburetors, improves gasoline mileage, extends spark plug life, reduces and prevents varnish and gum build-up. Added to oil it prevents valve sticking and clatter, fortifies properties of engine oil, prevents breakdown caused by extreme temperatures, reduces and prevents acid and sludge formation and promotes easier cold weather starts. For any further assistance, please feel free to call us at: 1-877-238-2623 or visit the nearest Advance Auto Parts store and one of our Parts Pros will gladly assist you with any questions or concerns you may have.

                Answered on 8/2/2013 by Steve from AAP
            • Q:

              Could you tell me the proper mixture for one gallon and a half?
              (motorcycle usage)
              Asked on 5/12/2013 by Parma from Lodi,OH

              1 answer

              • CUSTOMER CARE

                A:

                Adding Marvel Mystery Oil Fuel Additive, 16oz.(Part No. MM12R) to Fuel: Marvel recommends using 4oz of Marvel Mystery Oil for every 10 gallons of gasoline. It can be used (Marvel Mystery Oil) in diesel fuel as well as gasoline. For any further assistance, please feel free to call us at: 1-877-238-2623 or visit the nearest Advance Auto Parts store and one of our Parts Pros will gladly assist you with any questions or concerns you may have.

                Answered on 5/13/2013 by Max from AAP
            • Q:

              How much do you use if mixing with gas? with oil? And is it for any year cars or certain year vehicles?
              Asked on 1/16/2013 by Sandi from Clermont, FL

              1 answer

              • CUSTOMER CARE

                A:

                Adding Marvel Mystery Oil to Fuel: Marvel recommends using 4oz of Marvel Mystery Oil for every 10 gallons of gasoline. It can be used (Marvel Mystery Oil) in diesel fuel as well as gasoline. Use the same amounts as the gasoline treatment recommendations - 4ozs of Marvel Mystery Oil for every 10 gallons of fuel. However, Marvel Mystery Oil does not comply with federal low sulfur content requirements for use in model year 2007 and newer diesel motor vehicles., Adding Marvel Mystery Oil to Engine Oil: Marvel recommends replacing between 10 and 25 percent of your motor oil with Marvel Mystery Oil. For example, if the crankcase capacity is 5-quarts, add 4 quarts of your favorite motor oil and one quart of Marvel Mystery Oil. It is compatible with synthetic, semi-synthetic blends and regular types of motor oils.
                For any further assistance, please feel free to call us at 1-877-238-2623 or visit your nearest Advance Auto Parts store and our representatives would be more than happy to assist you.

                Answered on 1/17/2013 by Aaron from AAP
            • Q:

              Is this for oil treatment?
              Asked on 3/25/2012 by Anonymous

              1 answer

              • CUSTOMER CARE

                A:

                This Marvel Mystery Oil Fuel Additive with part# MM12R could be added to gas and oil. It extends engine life by breaking down and removing harmful deposits of sludge and carbon in your engine oil. When regularly added to your fuel, it helps keep spark plugs and fuel injectors free of carbon deposits, resulting in increased fuel economy.

                Answered on 3/26/2012 by Vincent from AAP
            Displaying questions 1-4

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