Marvel Mystery Oil

Marvel Mystery Oil is 70% Naphthenic Hydrocarbons. 29% Mineral Spirits. It can be used as a gas for its upper cylinder lube than it is a cleaner. I have used it in my 1969 Chevrolet that doesn’t have a catalytic converter and my old 2002 two stroke Mercury.

I have worries about adding it to my 2020 Tundra. It might flooded the catalytic converter and O2 sensors with oil/lubricant.

In the old days with lower catalyst efficiency standards (pre-2002) there would be no issue. But today’s catalytic converters are held to a higher efficiency (+-90%). I use tier one gas.

Thoughts?

 

It's commonly added to Avgas but none of us will ever admit to it.

 

Don’t use it. I’ve never used that stuff and all of my cars have lasted 100s of thousands of miles anyway. It’s unnecessary. It’s practically snake oil.

 

What is your goal? Cleaning or lubing? Maybe both? Have you used Berryman's B 12 for cleaning? Good stuff. If your plan is to clean rings with directly pouring it in the plug holes, you can remove the converters for a bit.

 

A fellow Jarhead was a Fueler. MCAS Iwakuni. They had 50 gallon drums of MO. Definitely common to add to AVGAS. Definitely not snake oil. It served its purpose in this case.

 

Various opinions here:
Marvel Mystery Oil | BobIsTheOilGuy

 

What is the perceived benefit in adding it to a vehicle (not an airplane) that has been proven to last 100s of thousands of miles with only the recommended maintenance? Whatever benefit is obviously not necessary for our application, which lands it in the unnecessary, and potentially just snake oil for our trucks.

 

It's good in the gas if you going to put a vehicle in storage. That's the only time I'll use it.

 

If adding anything to gasoline helped an engine perform better, don't you think the refineries would be adding it?

 

Not if it meant they could sell you more gas by leaving it out. Just sayin.

 

That's true. Has MMO ever been shown or thought to increases MPG. I....Or some dude at the airport...uses it to keep the valves from sticking but I....I mean he, never recorded any lower fuel consumption.

 

No.

 

Unfortunately, that is what we have to deal with….opinions without facts.

I started using it when my outboard mechanic started using his “secret mixture” when winterizing my outboard. He would not tell me all the ingredients. But MMO was one of the ingredients. I did notice the outboard started easier in the spring when he winterized my outboard than when I did. So, I started using it in my Chevy too when putting it away for the winter. But neither the Chevy nor the outboard have catalytic converters.