Marvel Mystery Oil50709 MM13R Mystery Oil-32 oz, 64. Fluid_Ounces, 2 Pack

I try to add this regularly, as my engine is high mileage

My engine is high mileage and wasn't looked after. Since using marvel mystery oil on each fill up and adding some too my engine oil it has definitely seen some improvement. Currently getting about 3mpg more and car is more responsive. Going to add 1.2L of marvel mystery oil on my next oil change to give it a gentle engine flush + protection. They have made a synthetic oil also but isn't on the market yet so I'll definitely get somewhen I can but I'd still use the original oil on each fill up.

I used it in my pots of an mg engine that has been sized for over 20 years, within 24 hours I could turn the engine by hand, so I put some more in and within a week I had compression on all 4 cylinders.You can't beat it. I purchased if in the usa, everything I've tried in the UK hasn't worked . Its just brilliant

Good

This mystery oil is amazing it definitely helped with gas mileage and it seems to soften the ping sound in my engine

Used it on a generator which was running rough. A few ounces and it began to run smoothly.