Friend is looking for a used car - he found Mercedes 300TD TurboDiesel, Wagon, 242k.

The car starts and runs very strong - it's in good shape, but I noticed that it had white smoke pouring out when it was first started and for several minutes of idle time. We drove it a while and it was a real rocket (compared to my 300D). After a hard ride the smoke was gone and the exhaust was completely transparent.

The coolant indicator light was on and the owner mentioned that the mechanic added some coolant to the reservoir during last maintenance interval. He also mentioned that the car may get elevated temperature when driven hard in the mountains or stuck in traffic...

I've read postings on this site that suggest that it may be coolant; other postings indicated that it may be unburnt fuel. Is there anything one can do to better assess what this car may be suffering from (if anything)?

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

You should read up in the archives about the cracked head syndrome. Basically if the cooling system hoses remain pretty stiff when the engine cools down. The head has a crack.

This of course is providing the cooling system is properly sealed. It is generally thought these engines will not tollerate high temperatures well.

Coolant indicator light could just be a stuck sensor in the reservoir.

What does the white smoke smell like? It will probably smell of unburned fuel, coolant or both.

Sixto
87 300D

White smoke is an indicator of coolant getting into the combustion process (one or more cylinders). Combined with the penchant of the 603 engine to crack its head or blow its head gasket when overheated, this is definitely a sign to you to proceed with caution. The lack of white smoke when the engine is hot could mean that the coolant is still there but now being completely turned into invisible vapor by the combustion process (we need to hear a chemist say that, though).

Note that the 603 engine is not more likely to overheat than the next engine but if it is overheated it is more likely to be damaged -- understand what I am trying to say? The early #14 heads are most likely to have this problem, later #17 and #22 heads were improved. My own '87 300D does not have any overheating problems at all but it was overheated by a PO so I have a new head (still #14, unfortunately).

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

If it IS a cracked head or blown head-gasket... what's a ball-park estimate to get that fixed, assuming that my friend does not have the know-how to fix the problem himself... ? Just a ball-park...

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

FWIW, my 124 sedan smokes a fair amount when started cold, but it's unburned diesel fuel. If you smell the smoke you can tell. It only smokes for about 30 seconds or so. Its worse in colder weather, though.

Get a pre-purchase inspection before you buy.

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1982 240 D, 308,000 - 321,127 miles (sold)
1982 300 TD,166,500 - 226,000 miles
1998 E 320, 120,000 - 144,000 miles
2005 C 230 K, 26,000 - 77,000 miles (sold)

Do a search of this forum and I'm sure you will find the answer re: price. As I remember from previous posts I've read, the part alone is well over $1,000, and labor would probably be similar. It would probably come to more than half the purchase price of the car. If you could get a mechanic to verify the head is cracked, I suppose you could talk the seller down...

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

Assuming it goes this far: is there a test a qualified mechanic can perform to in the garage to determine wheather or not the head is indeed cracked?!

__________________
1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

If the upper radiator hose remains very firm (as if it is under pressure) even after stopping the engine, it means that compression is getting into the water jacket. Presumably that also means that coolant is getting into the combustion chamber, causing the white smoke. Others here may have better ideas -- this is something I've never seen on a Mercedes and I don't wanna talk about my '63 Alfa Romeo.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Try German Motors in Lakewood. Mark is very good.

Price seems a little high given the dent in the hatch.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13