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25% Off All Online Orders of Select Parts and Accessories
Receive 25% Off Your Online Purchase. Use promotional code 25PEP at checkout to receive discount. Not valid in combination with any other discounts or promotions. Not valid on gift cards, special orders, installed merchandise, commercial or fleet purchases. Excludes the following categories: Tires, Wheels, Batteries, Powerstop Brake Kits, Oil, Antifreeze, Refrigerant, Truck Boxes, Vent Visors, Bug Shields and BRANDS: Razor, Traxxas, Superchips, Hypertech, Edge, Bully Dog, Diablo, Edelbrock, Holley, NOS, Proform, Specialty Auto, Thule, Autometer, Accel, K&N, Kenwood, Pioneer, Sony, JVC, MSD and BBK Performance. Valid online until 2:59 am EST on 12/12/16. Online orders scheduled for in-store pick up must be completed by closing on 12/11/16 for discount to apply.

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  • Part #: MM13R|
  • SKU: 118736

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    • Helps improve fuel economy
    • Cleans and lubricates fuel injectors and carburetors
PayPal available for online purchases. Major credit cards accepted online and in store. Pay online, in-store or take advantage of our Pep Boys credit card. Learn more and see additional details in cart.

Marvel Mystery Oil Oil and Fuel Additive

Since 1923, Marvel Mystery Oil has helped increase the life of countless engines of all types. Marvel Mystery Oil cleans the engine from the inside out while increasing fuel economy and protecting against temperature extremes. Regularly use Marvel Mystery Oil in your oil and fuel to enhance overall performance.
  • Helps improve fuel economy
  • Cleans and lubricates fuel injectors and carburetors
  • Reduces and prevents varnish and gum build up
  • When added to oil, prevents valve sticking and clatter
  • When added to oil, prevents oil breakdown caused by extreme temperatures
  • This item must be picked up in the store as it may contain materials which are flammable or corrosive.



Rated 4.7 out of 5 by 53 reviewers.
Rated 5 out of 5 by Awesome product I love this product! It works wonders for my truck August 22, 2016
Rated 5 out of 5 by Works great My engine is quiter and more throttle responsive August 11, 2016
Rated 5 out of 5 by Good additive for fuel I've been using this product for years with older cars that are driving on original injectors this product has proved to maintain as well as when I began, clean injectors in my 1995 and 2000 vehicles. August 10, 2016
Rated 5 out of 5 by Works as advertized I have known of this product for years. I even sold it to people when I worked in a parts store during my college years. I recently tried it on a high mileage SUV. I am now a believer. September 10, 2016
Rated 5 out of 5 by Very good product, excellent additive for any engine. I have used this product before and it functions well in any engine I pour it into. I believe what it states on the label and will use it again. September 1, 2016
Rated 5 out of 5 by myster oil Have used this product for years. It always does the job. A friend saw me using it and was surprised it was still available. Told him to go to Pep Boys on the Concord Pike, and he could buy it there. August 23, 2016
Rated 5 out of 5 by Great Product! This product works fast. The engine always hesitated once the Marvel Mystery was added this product seemed to work really well. So far have experienced no more sputtering of engine. Thanks Pep Boys!!! October 10, 2015
Rated 5 out of 5 by Product was fabulous, does what it advertises! Easy to put in clear instructions as to what to do. My engine is Happy now. August 9, 2015
Rated 1 out of 5 by can't see it did any good at all did not get what i expected September 22, 2015
Rated 5 out of 5 by Marvel Mystery Oil and Fuel Additive I have used this product for over 30 years- been around as long as dirt- great dependable product. Highly recommend!!! September 2, 2015
Rated 5 out of 5 by Great stuff I always Use I get better mileage using this product August 31, 2015
Rated 5 out of 5 by Verry good product Good not only for 4 astroke eng. but also 2 strokes August 28, 2015
Rated 5 out of 5 by Marvel Mystery Oil Wonderful all year product August 22, 2015
Rated 5 out of 5 by all a round never hurts, add to oil, gas.. June 21, 2015
Rated 5 out of 5 by Always used it and always will! I have used this in my cars and motorcycles for years. If you ever wondered why Diesel engines last so long, this is why. Diesel fuel is essentially an "Oil". It lubricates the upper cylinders and valves/injectors etc... Add a little to your fuel tank at fill up and listed to how quiet your engine gets and how smooth it feels. Get it on sale with the 30-35% coupons! July 17, 2015
Rated 5 out of 5 by DON'T LEAVE HOME WITHOUT IT!!! gives my jeep an additional 3 miles per gallon!!! pays for itself! May 27, 2015
Rated 5 out of 5 by good product I've been useing this in my 95 Mazda B3000 for years. It inprove gas milage & engine performance. I've got over 250,000 miles on truck & this product has reall helped May 20, 2015
Rated 4 out of 5 by use as a gas additive I have used mystery oil since before I could drive .It has extended the life of my engines in my car boat and 2 stroke engines. I have never had a car go less than 200k when I have used it in my gas February 10, 2015
Rated 4 out of 5 by Works well Engine seems to run smoother with slightly better mpg when adding to fuel tank at every fill up. January 19, 2015
Rated 5 out of 5 by Simply gets its job done rite! Out off all the additives for motor oil and/or gasoline that I have purchased and applied to my 98 camry le as specified on the labeling over a period of 2 weeks, MMoil is by far the most bang for my buck! You can definitely feel the difference in performance after properly applied to both the engine oil and gasoline as specified. I give this product a big A+ January 11, 2015
Rated 5 out of 5 by Does what it claims to do. I usually use this product before a long distant trip in the gas tank and also some in the engine oil. It performs as it states. Smooth engine running and more complete gasoline burning. I have seen a slight increase in MPG when using this product. I will always give it a high recommendation to others. January 9, 2015
Rated 4 out of 5 by This product is quite good I read an article on using Marvel Mystery Oil in both fuel and oil. Helps stabilize both. Helps gas tanks from rusting and helps clean fuel lines and carbs. December 29, 2014
Rated 5 out of 5 by Excellent as usual Great for your oil and gas - takes all the knocks out in your engine. - smooth ride December 5, 2014
Rated 4 out of 5 by Marvel Mystery Oil My older low compression aircraft engine needs MMO to prevent valve guide problems. December 3, 2014
Rated 5 out of 5 by A welcome sighting Was looking for an additive to try and stop some tapping coming from my wife's motor. As I walked down the aisle I saw an old friend from my teenage years. I picked some up and it seems to work as well as it did years ago. Marvel Mystery Oil can be added to your oil and gas. I did both and the tapping has diminished greatly. January 2, 2015
Rated 5 out of 5 by have used marvel oil in all my vehicles marvel oil is good for your oil and gas,will make your vehicle run smooth quiet,gives grea gas milage.can use on older and newer cars/trucks.i have been using it for the last 15years or more. December 17, 2014
Rated 5 out of 5 by Great product! I have used this for some 40+ years on all types of engines. I use it primarily in the gas tank as a top lubricant. I have put 100000+ on at least 6 vehicles and my current work SUV a 99 Dodge Durango with 145000 runs well. I have also extended the life of several mowers with its use! December 16, 2014
Rated 5 out of 5 by Marvel Mystery Oil Seems to help my engine December 16, 2014
Rated 5 out of 5 by Marvel Mystery Oil I have been using this product for over twenty years now and have never had a problem with using it yet. A great product for gas additive and oil additive. Will never stop using it. Buy some and try for yourself. December 8, 2014
  • 2016-12-07 T09:44:24.067-06:00
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