A few months ago, I purchased a 1991 300D at a great price with 238k miles. I've been fixing things as I go, but I have been using this car as my DD for the last couple of months, and it's never let me down.

The car will sometimes produce white smoke from the exhaust. It's an intermittent issue, and sometimes a full week will go by with no smoke. BUT when it does smoke, it can be quite embarrassing. Maybe that's why the PO installed tinted windows?

This smoke usually happens when I have been driving for at least 30 minutes (engine is warmed up), with lots of idling or stop-and-go traffic. During an "episode", I will begin to see puffs of white smoke from the exhaust. Then, it gradually thickens for about 30-60 seconds until I start driving again. Sometimes the car continues to smoke after I pull away, but never more than a minute or two. After that, there's no more smoke for the remainder of my trip.

I already replaced the DV seals and torqued them properly. I have also checked for any leaks in the fuel system - other than some wetness on the IP (shutoff valve seal gone bad?), it looks fine. The injector nozzles definitely need to be replaced, but I'm not sure if they would cause any white smoke. I cannot detect any sweeteness or "coolant smell" in the exhaust, nor any "milky" engine oil or oily coolant that would indicate a head gasket issue. The engine never overheats, and is almost always below 80 degrees.

I thoroughly cleaned the IP when I replaced the DV seals, but the old rubber o-rings had partly disintegrated when I pulled them. Could the smoke be caused by debris in the IP from the old o-rings?

All the research I have done on white smoke points to a head gasket issue. Based on my description of the problem, is that the likely culprit? I'm hoping to see if there's any way I can further diagnose the problem before pulling the head.

Are you losing coolant ?

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

Well as the previous post indicates you want to establish if it is oil or coolant first. Coolant with anti freeze should have a sweet smell and condense on a mirror. The mirror is held just behind the tailpipe while the engine is smoking. Oil smoke will not condense on the mirror.

There are several tests if it is oil smoke to do. If oil smoke I would suspect the oil pressure feed to the head located just ahead of the first cylinder in the block and head. Failure of the head gasket there on these engines is not uncommon and it could be intermittent.

Usually you prove the problem is there first before removing the head. There is enough of a chance if the smoke proves to be oil to test for that problem. Although that is just my opinion. Smarter members on the site may have better approaches.

Sounds like head gasket to me. Very similar symptoms on my 92...and at about the same mileage. Mechanic doubted it was the head gasket....I asked him to remove the head to humor me....it was the head gasket.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

LOL

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Yes, I believe so. I looked in the reservoir tank today, and the level is about 3/4" below the max fill mark. The coolant itself also looks a little cloudy.

I called around to a few shops today, and they are quoting about $3500 to change the head gasket. Given that the car has a fair amount of rough edges already, I'm considering just trading this 300D for a better example. A dealer in my area has a nice '92 W124 diesel for $5k. It's very tempting!

Why not look for a 1995 E300? You should be able to get a nice example in that price range, it may just take a little longer since they're somewhat rare. The OM606 only came in 1995 and is far superior to the rest of the W124 diesel IMO, and head gaskets are all but unheard of, plus it has no turbo to worry about, and still the second fastest W124 behind the 87 300D, but it gets the best fuel economy of the bunch to boot...as you can see I'm quite smitten with mine

If someone has had the head done it's usually due to severe overheat or a poor mechanic breaking off one of the long glow plugs in the head, thus requiring removal.

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1995 E300 Diesel
~300k

$3500 is outrageous. I paid $1500 a couple of years ago.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I may just do that. All due respect to the W210 fans out there, it's not my style. I much prefer the W124, and combined with the 606 it would be a great car.

shertex - I agree that $3500 is a lot, but it includes having the head sent to a machine shop, plus replacement of the valve stems, guides, and seals. I called several independent shops in my area, and that was the average.

Very hard to go wrong with a 95 E300. Other than the wiring harness, they're bulletproof. Need to get me another one at some point.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

There are various engine block sealers on the market that ranges from under $10 up to $70. This one is $9 CRC/Permanent Metallic block seal 1016- ReadReviews onCRC #1016

May want to do some research and try one? What have you got to lose? It may work.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yeah they are, I absolutely love mine. It runs awesome at 80mph out in the desert when I take trips out there. I tend to average 37mpg if I keep it around 70mph on the flats, and that's in extreme high heat with the A/C running.

If the wiring harness has been done, they're golden. You could probably find a nice E300 with 150-200k miles on it for maybe $4-5k, that's almost as much as a new HG on your car at this shop.

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1995 E300 Diesel
~300k

Block seal is usually water glass / sodium silicate. The stuff does work and is stealth so it might already have some in it.

_THE_ only properly way to check for a combustion chamber to coolant leak is to do a leak down test. This is where you pull a glow plug / spark plug / injector, put the piston to TDC with both valves closed and pump in ~ 100 PSI of air and see if it comes out the rad / coolant bottle ( with the cap off. ) This will narrow it down to a specific cylinder that you can later check for the exact point of failure.


For most engines, a oil to coolant leak through a head gasket is rare. Coolant to oil is possible on some engines. Coolant to outside of engine is semi common. None of these can be detected my a leak down though and none of them will show up in the exhaust.