The backstory is that car starting idling really bad and smoking a couple of weeks ago. The smoke smelled like coolant. It did not overheat.

I'm hoping y'all will help me figure out what exactly happened -- gasket failure or head failure. I have pics of the rest of the gasket, head and block, but these are the most gruesome of all. The rest of the cylinders look good.

You might be lucky. Just looks like the head gasket was deficient. Head will have to be checked carefully to find out if still flat especially. Good ideal to have the head checked for cracks as well if not too expensive. Hope all goes well it could easily have been worse. This may have come on gradually I think there are two distinct areas that lost the seal.

Thinking warped head - just send a straight edge, even a carpenter's square is sufficient, across the mating surface - if that is the original gasket, there isn't much reason to believe that it was faulty since it already had ?how many? trouble free miles.

Was this sudden, what were the signs, did you change your fuel mix recently, is your cooling system in check.. etc?

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I wiped everything down a bit with a paper towel.
I'm not sure what I should be looking for with a failed gasket... should a section be blown out? I think the crack that you see on the gasket between cyl 1 and 2 happened when I was wrestling the head out.

I also considered that as there are the two distinct areas on the gasket. I also wonder what a crack check is worth on all the head. Maybe he can post a price he is quoted.
He may decide against it if all the other cylinders appear very simular to each other. Depends on the cost I guess. A good flatness check of the head is mandatory. If it is still flat by some miracle I would then check the top of the block as well.
I was weighing something else as well that is not discussed much on site. The aspect of it not being a good ideal to come off the highway and shut the engine down right away. If the car is just idled for a few minutes it tends to equilize any hot spots.

In the old days especially it was just considered good practice to allow some run time before shut down. I still do it especially if just coming off the highway. True or not it cannot hurt anyhting and could very easily be true.

251,000 miles. Sudden with the idle and smoke, but the car always seem to consume coolant. About a quart every couple of months. I've had the car 2 years (30k miles).

the gasket was not sealing. save yourself the headache and send the head to a machine shop to be checked and milled. it looks like it is warped and not sealing between cyl 1& 2 i cannot see anything very wrong with the gasket from your picture

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97 e320 200k!

85 300sd

96 c280 sport for parts! pm your needs

do you see the difference b/w your head and this iron head from a 240d?

It appears you have an exchange going on b/w cylinders. The markings from exhaust / staining would not be there other wise. Each cylinder should be perfectly sealed and the rings should like the better 75% of #1.

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Anyone know or remember the amount of material you are allowed to remove from these heads? If the machine shop says it needs more there are places that can straighten a head somewhat before milling. Any shop that mills heads has a book of material removal allowances for all heads.
The prior cooling loss was probably past part of the gasket before the other area between cylinders started to leak eventually as well. Or it could still be because of a crack in the head. Or a leakage point anywhere else in the cooling system. Actually the sealing between cylinders number 2&3 does not look perfect either.

Can you take close ups of the cylinder head in the #4 and #5 cylinder area?

Sixto
87 300D

3,4 & 5


4,5 & 6

You can tell by the rings on your head that it was at one time properly seated, then the soot filled in over it.

I would def say cooling malfunction, but I wonder what part age plays in the warpage of these heads - repeated expansion and contraction.

I don't think idling your car cools the engine, driving on the highway at a constant speed, low load provides the most air flow to heat ratio.
Hot coolant remains in the head (or it should with a proper system) after shut down, it isnt like sending cold water through there.

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Yes, I totally see the difference.

sorry, homes

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It'll take better eyes than I have to confirm but I think I see a crack between #5 exhaust valve and the prechamber. If so, that's where coolant leaked into the combustion chamber... and the head is toast.

I could be wrong because a cylinder burning coolant would have ash and other discolorations.

Sixto
87 300D