1992 300D 2.5 SMOKING LIKE CRAZY help :( - PeachParts Mercedes-Benz Forum

nehuge · #1 11-11-2015, 06:23 PM

170k on this 1992 2.5 turbo (OM602)... last week it started smoking white/grey out the pipes and knocking. It isn't black or blue. It burns the eyes. I'm talking smoke like I'm doing a tire burnout!

Anyway, I was due to put in new injectors anyway so I had Monark nozzles put into my injectors by a Bosch certified shop. Prechambers looked fine and had the ball inside still. Torqued the injectors back to 59 ft lbs and had new brass crush washer in (the correct orientation too). It made no change.

I have no water on the dipstick, and no oil in my coolant reservoir.

Any ideas? One shop looked at it and the knock and smoke and said it seems like something internal. They didn't want to touch it. Another shop just by a discussion with them said perhaps a hole in the piston? They also said that a head gasket replacement would be more expensive than the motor they have lying around with 210k miles on it. It has had the top end replaced and has rebuilt valves, seats, etc. Expensive, but heck most people have $450 a month car payments and this would pay for it in like 3 months.

Only thing I did was the day before this happened put some Lucas injector cleaner in. I have flushed the tank and run it on new diesel, no change.

Perhaps I can get a video with sound of it running and throw a Youtube link on here, but with the knock and smoke I hate to run it for long. It's 75 degrees here now so everyone's got their windows open in the neighborhood and I can't crack one injector open at a time while this thing smokes my street.

A vacuum pump was installed by a shop 2 weeks prior. The grommet for the stop lever was replaced, and of course injectors. Also, a little 2 inch vacuum line was replaced (the one that goes into the top of the white plastic stop valve) with a slighter smaller diameter hose.

Any ideas? Can't they do a compression test and put a scope inside the prechamber holes to look at the pistons, etc?

shertex · #2 11-11-2015, 06:54 PM

My guess would be head gasket. When mine went bad on my 92 at 243k, I had the same smoke but no evidence of oil in coolant or vice versa. Mechanic didn't think it was the head gasket...thought I needed a replacement engine. I told him to open it up anyway to see what he saw....it was the head gasket.

dieselbenz1 · #3 11-11-2015, 07:00 PM

X2 head gasket

vstech · #4 11-11-2015, 07:05 PM

There is a recall on some 92/93 602 turbo vehicles. .. Pull the valve cover and look at the cam gear... if the teeth are SHARP with no flats you could be covered...

pwogaman · #5 11-11-2015, 07:14 PM

Quote:

Originally Posted by vstech

There is a recall on some 92/93 602 turbo vehicles. .. Pull the valve cover and look at the cam gear... if the teeth are SHARP with no flats you could be covered...

Can you please share more details on this recall? This is the first I've heard of it.

Mxfrank · #6 11-11-2015, 07:29 PM

First, let's do a little research. Here's what I suggest you do:

1) Remove the accordion tube between the air cleaner and the turbo. Is there oil on the turbo compressor wheel? Is there oil inside the accordion tube? Are you losing oil?

2) Are you losing anti-freeze? Is there any sign of oil in the coolant?

3) One by one, undo the connector on each injector until it starts to leak, then tighten. For each injector, this should cause idle to become rough until you tighten it back. Does this happen with each cylinder?

4) Smell the fuel. Does it smell like Diesel, or something else? (someone may have added gas to the tank, rather than Diesel)

Forget a borescope inspection. The only way that would work is if you pull the prechambers.

vstech · #7 11-12-2015, 02:57 AM

Quote:

Originally Posted by pwogaman

Can you please share more details on this recall? This is the first I've heard of it.

In the mid production of the 602 MB installed timing gears without the hardening process done, so a LOT of them wore out and caused chain failure and excessive timing issues...

shertex · #8 11-12-2015, 04:29 AM

Quote:

Originally Posted by vstech

In the mid production of the 602 MB installed timing gears without the hardening process done, so a LOT of them wore out and caused chain failure and excessive timing issues...

But I believe it was only MY93 that was affected by that.

ah-kay · #9 11-11-2015, 07:22 PM

My money is on the turbo if it smokes like a chimney and produces a stream of white smoke while driving. Been there done that. This is what I would do.

1) Do a compression test, ideally with hot engine to make sure they are all within spec. That would rule out the piston or head gasket.
2) Drain all the coolant out so the engine is deprived of water. Run engine for a short while. If it still smokes then it is not the gasket.

nehuge · #10 11-12-2015, 10:00 PM

Okay so the shop looked at it. They removed #1 injector, and as it ran it spewed oil out. They think at least a head gasket. Additoinally, they did a compression test on #1 and it was 240, "wet".

They said about 3 1/2 hours to get into it to verify it isn't just the gasket, and from there they'll go all the way or do a swap with a rebuilt OM602 they have in their shop. What do you all think?

They didn't do leakdown test. The did bypass the turbo completely and same result. As stated before, no oil in the coolant, no water on the dipstick and the levels haven't changed (then again since this has started smoking I haven't run it that much for fear of all the knocking that is going on), but in that little amount of time I think the oil is down on the stick some. It created so much smoke that I couldn't afford to run it long enough to crack each injector open before it smoked out my whole street.

What do you all think? Keep this puppy around? Here some pics, I'd hate to get rid of it it has 170k miles on it and was babied. With most people having $400 car payments per month, this'd be a few months of those. Hard to eat all at once however. Just because I have a Mercedes doesn't mean I have money! I think I don't have money because I have a Mercedes! lol

the D · #11 11-12-2015, 10:15 PM

Wow, that thing is in great shape. You gotta fix it and keep it. Just my opinion though

Mxfrank · #12 11-12-2015, 10:17 PM

A head gasket isn't the end of the world. Not sure there would be any way to verify that that's the only problem without removing the head.

dieselbenz1 · #13 11-12-2015, 10:45 PM

I'd get it repaired likely just the gasket mine was replaced twice. Where about are you I may have an interest in the head your mechanic has.

Chris W. · #14 11-13-2015, 08:37 AM

That car is nice! Do the repair.

Rgds,
Chris W.
'95 E300D, 453K

Maxbumpo · #15 11-13-2015, 08:58 AM

I'll bet that the head gasket has ruptured at the oil passage, and is dumping oil into the #1 cylinder. The latest head gasket from MB should be upgraded in that area to strengthen that passage to prevent this blow-out again in the future.

Please have the shop measure and compare all the piston heights to determine if the #1 cylinder was hydro-locked by the oil and bent the piston rod. If the rod is bent, that piston will wear out the cylinder bore and may eventually fail catastrophically. If the cylinder bore is already wearing away, then you may need to get the replacement engine, depending on the extent of the wear. Ideally, if the engine oil was always changed on schedule, all the cylinder walls will still have the cross-hatch marks from the factory honing process, which will indicate no wear, but they still need to measure the piston heights to see if the rod is bent.