As I said in my last post, I have used it in every tank since new. I do not use it in the crankcase of my tundra because I run syn oil. I do use it in the crankcase of the wife's 91 honda civic. I tried 1 oil change in her car w/out the MMO and the engine had a viberation to it that was not there where I used 1 quart MMO. I haved used it in the crank case of all my previous vehicles (1993 S-10, 79 Pontiac Trans Am and 79 Pontiac Firebird). These are just some of the questions copy and pasted from the marvel mystery oil website.
Is Marvel Mystery Oil safe to use in today’s “high-tech” cars?
Yes! Marvel Mystery Oil is completely safe in today’s high-tech cars and provide the same benefits as it has since 1923-cleaner engines, upper cylinder lubrication, reduced acid and sludge build up, improved fuel economy, clean and lubricated fuel systems and many more!
ADDING TO FUEL
How much Marvel Mystery Oil (MMO) do I put in my gasoline tank?
Marvel recommends using 4oz of MMO for every 10 gallons of gasoline.
Can I use MMO with every fill-up?
Yes. In fact many Marvel users who use MMO with every fill-up report significant increases in fuel mileage.
Will MMO cause any damage to oxygen sensors, fuel sensors or catalytic converters?
No. MMO has undergone rigorous testing to ensure the safety of all internal components in your vehicle including highly-sensitive oxygen sensors, fuel sensors and catalytic converters.
Can MMO be use in vehicles with fuel injectors?
Yes. MMO can be used in vehicles with fuel injectors. MMO provides additional lubrication to the injectors and helps prevent the formation of hard carbon deposits on the injectors. Injectors fouled with hard carbon deposits do not perform optimally and reduce mileage and performance.
Can I use Marvel Mystery Oil with diesel fuel and if so, how much do I use?
Yes, you can use MMO in diesel fuel as well as gasoline. Use the same amounts as the gasoline treatment recommendations-4ozs of MMO for every 10 gallons of fuel. However, MMO does not comply with federal low sulfur content requirements for use in model year 2007 and newer diesel motor vehicles.