Bklyn

Back in the 70's and 80's, I used Marvel Mystery Oil on all of my cars. (Oil additive as well as gas additive). Never had a problem with any of this cars. My 08 S 550 has 134,000 on the clock.

Anyone have any experience with this stuff in an S550?

Any opinions GREATLY appreciated. (As an aside, I have been reading through the over 500 reviews on amazon with 92% of the reviews being either 4 or 5 stars. See the URL if you have any interest.

steveb9771

Recent Mercedes owner manuals state "! Do not use any additives in the engine oil. This could damage the engine." Some older manuals state that engine warranty is void if oil additives are used. Most, if not all, of the reviews are not based to scientific data, they are simply opinions. The ones that claim it really works are for vehicles built prior to 2000 which had mush looser tolerances and did not use synthetic oil.

Only use synthetic oil that meets Mercedes 229.5 specification such as Mobil 1. See https://bevo.mercedes-benz.com/bevolisten/229.5_en.html for a listing of all approved motor oils for your vehicle.

Use only toptier gasoline with no additional additives. See https://toptiergas.com/licensed-brands/

Under no circumstances add this product to your gasoline unless you are prepared to spend over a thousand dollars when i ruins your catalytic converter!

Techron can be used as a fuel additive if you are experiencing rough idle due to dirty fuel injectors which is extremely rare if you have been using toptier gas.

Bklyn

Steve, one of the reasons I love this place is that I can tap in on the expertise of folks just like you. I thank you!

DaleB

The only real "Mystery" about MMO is why people still think it provides any benefit.

pb39374

See attached doc from MB, I know it’s old but the only non-MB fuel additive that MB recommends is Techron. The W221 is part of the list on page 15.

Shadly1

It smells good

Bklyn

This is so funny because I have always loved MMO smell.

Bklyn

This is AMAZING. Thanks

Promo Bob

Big fan of MMO, (reluctantly) used it gas,then oil, of tuned Audis. Works amazing, especially for the price ($3.62@ Walmart). Used it for years now, still add sometimes to gas nowadays. But then upgraded to the Liqui Moly Ceratec, MO2S, Molygen, . ..etc.. another level of performance!! Excellent for 4rings, Mercedes... Details in other threads posted here.

chirboiz,

Bob

bmwpowere36m3

Meh... light oil and naphtha, like older SeaFoam variety. Newer SeaFoam contains PEA, which is actually a proper cleaner as found in Techron among others.

A relic from carb days... I’ll use SeaFoam in small engines. Cars get Techron, BG, Redline or Gumout.

The Thomas J

I was using MMO as recently as this past spring. It's basically suped up tranny fluid. I use it if the power steering fluid is low in any of my trucks or vans. I would put half a bottle in the fuel tank of my old Freightliners with 3126 CAT motors. It always cleaned them out really well, and I would put the other half in the crankcase the day before an oil service. I got over 650,000 miles out of both those engines and they still run. They outlasted the trucks that they were in which was very unusual for a CAT 3126.

RussZTT

Ive used this stuff for years. I even use it on my CLS 63 once in a while adding it to gas. No issues.

BOTUS

oils have moved many many leap years in the last 15 years
and worse manufacturers have moved to fun and games

this is not BS its fact, Manu now build cars with various components that ONLY cope with the oils they recco - they idea its to catch you out and make it fail faster
to stop u guys taking them to court they have wrapped it up in BS stop start needs, and in the need to move forward on longevity of the emissions system components

if you add old world clever stuff it will cause harm to a modern engine - manu recco full specification or don't drive it

kevm14

I wouldn't use MMO as an oil additive but I would consider using it as a flush in certain situations. It's a great engine fogger and does a lot of other cool stuff, too. MMO is good to have on hand if you tinker with really any kind of machinery...