I see that I replaced my w201 head gasket 10 years ago at 82,000 miles.
Today I need to do it again! @120000 miles.

Did I do something wrong or is it just old age?

That seems VERY low mileage to have to replace a head gasket. Any overheating that you know of?

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

It’s been slowly losing coolant for a while with no other symptoms. I only, drive about 2000 miles a year now. But today oil in the reservoir. I wonder if so little use has an impact. The first replacement was after buying it from a 90yo man, who probably wasn’t driving it at all.

For 8 years the cooling system held coolant without fail. It’s been rock steady at the gauge and even yesterday, with oil in the tank was right at 85 d c. But has been asking for more coolant lately. It dropped level an inch or so over the winter, when it was asleep, so I was hoping for a frost plug. But couldn’t find an obvious puddle.

Oh well. I love this car and this has been its only repair in 10 years. It runs great even now.

If I understand you correctly, you suspect the head gasket because you can't see evidence of a leak. Since it is running fine I would suspect that it is not a head gasket problem. You can run a test to determine if there are combustion gases in the cooling system, which is a sure fire test for a blown head gasket. Some Mercedes like my 606 can leak coolant from the head gasket with out involving the combustion chamber or the oil system. In my case the coolant weeps out around the head gasket behind the exhaust manifold, leaving a white deposit on the block. The deposit is likely silicates from my antifreeze, but they are quite common in antifreeze's. So check the block for white deposits. I have been controlling my coolant leak by using a Barr's leaks Radiator sealant, for many years. This will raise the ire of any mechanic, but my old diesel is happy with it. I only add a few oz when needed. It will go many months without leaking at all.

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'97 E 300 D

What engine and were new head bolts used or were the old ones measured for stretch? Was the head resurfaced and the block checked for straightness?

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Oil in the reservoir. No evidence of external leaking, but I will double check that before I get into,this.

Last time I used new bolts. Checked for flatness with feeler gauge and 12” steel ruler, not ideal I know. No history of overheating. What brand of head gasket do people like? Copper spray or not? Im pretty disappointed in this but in 10 years this is the only hiccup.

I’ve had three of this model, and done two head gaskets. It might be a feature. Not hard to do, just tedious.

I would recommend Victor Reins head gaskets.
I believe they also offer a slightly thicker version to account for minor surface imperfections.

Instead of the copper spray, you may want to consider Hylomar spay sealant on the gasket.

Make sure to thoroughly clean out and chase head bolt holes. A little grit and or oil in the hole base can prevent the bolts from fully seating.

Also note, some engines call for the head bolts to be retourqued after approx 500 miles.

Good luck, hopefully this one will be that last one.

Just got back here. Thanks for the gasket suggestion. The car goes to,the spry young mechanic for a final diagnosis. I “think” the car lost coolant sitting over the winter, which would rule out head gasket, but from the top looking down I can’t see any other place that shows coolant loss.

I’ve always chased all head bolt threads and vacuumed them while applying brake cleaner.