I have carbon build up on my #4 and #5 fuel injectors and I saw that others on this forum suggest cleaning the injectors by soaking in Marvel mystery oil for a few days. I mentioned this to my mechanic and he said that MMO is too strong so do not do it. I thought I might try to see what soaking the one injector in the MMO will look like after a few days and compare it to my good injectors. Has anyone else tried cleaning really dirty injector with marvel mystery oil?
Does anyone else agree with my mechanic and am I asking for trouble by not following his advice? I figure I have nothing to lose, it is already a goner otherwise. Maybe I'm crazy.
Frankie

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Frankie
It never ends!
1985 300D Turbo 181K Anthracite grey, "SOPHIA"
1984 300 SD Turbo(sold)
2004 Subaru Forester XT,Cayenne red.

I never thought of using MMO for such a task. I have used biodiesel in the past. It works quite well

It's an oil, not an acid. Don't see how it could hurt anything.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I substituted MMO for Diesel Purge when I chose to clean my injectors. Sucked that stuff right up, and ran straight on it for about half-an-hour to consume the entire quart (I was operating the engine at random speeds).

Diesels idle like glass, and the power and fuel economy are phenomenal as they have been for 5K miles since.

It will shock you how quiet these 60x engines can really be. Almost have to put your ear down to the engine to hear it purr. Not sure about the 617.

Time to post another video.

imho you couldnt hurt an injector if you let it soak in the marvel oil for a year.
i have experimented with the same oil to try removing carbon from aluminum pistons and it just wont do the job, matter of fact engine oil did the same results.
i take brake cleaner, use a brass bristle brush and clean the outside of injectors. just be cautious and dont drop the injector and ruin the point on the plunger.
of course i completely dissamble the injectors and completely clean the entire unit,i have a strong solvent(porter t2) to soak all parts.most time there is rust inside.
hope this helps
larry perkins lou ky

Snake oil thread? Does anyone know the active ingredients in marvel mystery oil? It did seem to free up gummed or coked rings on a 617 run on unheated vegatable oil by soaking.
The knowledge of what exactly it worked on is unknown as the rings where not visible before treatment. Plus it cleaned out gummed up prechambers as well.
Interesting observation that used as a purge the one gentleman liked it. My one original small concern was that like good expensive current penetrationg oils it does have an acid additive like sulphuric acid. It may not but there is some strong active ingrediant in it apparently if it cleaned out the injectors when running on it for about twenty five minutes. A straight type of oil would not have changed anything in my opinion.

I have heard of persisting with an endevour until you go blind. . Watch out for the marvel mystery oil fumes when using it as a purge. Your hearing and sense of motion might be comprimised. Larry, if you feel a weeks soak in this oil would do no harm then it should be safe as a powerful diesel purge as well in your opinion?

what could it honestly do to the injectors?
u would literally have to soak them in acid or straight water to cause damage, it says right on the bottle " use to lubricate and keep injectors clean"

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82' 300SD

This is helpful and leads to more questions too. Like trying soaking the other injector in biodiesel. Too bad my fueling station ran out of B99.
I do not know the ingredients of MMO. It doesn't state on the bottle. All I can gather from the bottle and their website is that it has petro distillates. It has no silicone, no methanol and no sulfur.
It is compatible with biodiesel according to the FAQ's.

I'm looking at the glass bottle that has the MMO soaking the injector and the ring. The injector nose has a scant amount of carbon coming off of it. It has been soaking for 2 hours so far. I'll put the bottle inside the house now and return it to the patio in the morning. Should be about 65 F tomorrow. I'll do this for 3-4 days.
Should I fill the cylinder up with MMO, biodiesel, or Detron III ATF fluid?

Frankie

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Frankie
It never ends!
1985 300D Turbo 181K Anthracite grey, "SOPHIA"
1984 300 SD Turbo(sold)
2004 Subaru Forester XT,Cayenne red.

go for the mmo, it wont coke up the rings like large amounts of tranny fluid will.

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82' 300SD

Ubrwgn-
How long did it take for the biodiesel to clean your injectors? How long did you have to soak the injectors in it?
Frankie.

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Frankie
It never ends!
1985 300D Turbo 181K Anthracite grey, "SOPHIA"
1984 300 SD Turbo(sold)
2004 Subaru Forester XT,Cayenne red.

Frank, my injectors weren't bad. I soaked them for a couple of hours. BD is a very good solvent. As the others have said, what can the MMO harm? I don't understand the mechanic's concern.

ok guys i wont even try to discount any stories about purging with suscess,but for me i have never been able to fix a bad injector with a poor spray pattern or one that leaks with any purging fluid. maybe i aint holding my mouth right.
if a nozzle is worn out u got to replace it with a good one, if its dirty-rusty you got to take it apart and clean it. as i said i use a strong solvent,i suppose i could get the same results with oils-penetrating-wd40-pb blaster, but i dont want to take the time to fool around and it always takes some scrubbing to get everything off the injectors.
just my experience.
larry perkins lou ky

Thanks Larry, this is why I am considering using biodiesel, it is a solvent . I have nothing to lose, and it can be a good experiment as to what does work.
I am willing to buy new injectors if this doesn't work.
F.

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Frankie
It never ends!
1985 300D Turbo 181K Anthracite grey, "SOPHIA"
1984 300 SD Turbo(sold)
2004 Subaru Forester XT,Cayenne red.

Friankie - Is my opinion that whatever build up in your cyl that was created on your trip last week should be burned away as soon as you fire it up with good injectors and run it a bit. I've seen you drive too; everyday is italian tune up day.

If you fill the cyl, how are you planning on getting it and whaterver crud it loosens out? Starter motor and blow it all over the engine compartment or turkey baster? I wouldnt stick the inj back in and start it, you'll likely do harm.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)