I have a 1987 300 D with 260000 miles. Recently it started overheating, I changed the thermostat, flushed it and it seemed to be ok. Then one night while I was driving the needle went really high and I heard the dreaded bubbling inside the car. I started down a hill around 50 mph to find a place to pull over and the car engine just stopped. Well, I pulled over, opened the hood, steam coming out, and the reserve antifreeze tank lid had blown off, and all the antifreeze had come out. After it cooled I added some water to the tank and noticed oil in the reserve tank. I took it to a mechanic he told me it had a blown head. I have not done anything further with it, so my question is what is the best approach to dealing with this sort of problem, and the estimated cost in your expert opinion to fix it. My guess is that it either needs a new engine (a blown head is a big job, potentially engine is locked up, and that is why it will not turn over). Been repairing this car for years through the forums advice, and know someone out there has faced this problem before. Thanks for your help.

 

If the Head is Aluminum it is extremely possible the Head is now warped or even cracked now.
In order to see if the Cylinders were damaged the Head would need to come of or it would need to be examined with a Bore Scope by removing the Prechambers and looking into each Cylinder.
Even if it turns out the Head can be reused as is with just a new Head Gasket there is no gaurentee that the heat did not distort Cylinders or soften Piston Rings. I say this because there is not an easy way to tell how hot it got and for how long.

So for someone not doing the Head removal themselves it is going to be some expense just to see what you could do next.
Also not very much can be taken off of the Head to resurface it.

 

Added: I do not believe anyone can estimate the cost because labor to repair cost vary too much depending on where you live.
And, in any area you would find some shops with resonable labor rates and others that are way out of line. And, paying more dose not always get you better quality Mechanics.

The above is one of the main reasons people do their own work.

 

Well it did see it redlined for more than a half hour before cutting out
(always ran a little hot), and all that makes sense. Probably not a job I can do, one estimate with parts was 5K, suggestion was to either to find a new engine at a junk yard, or junk it. I actually thought they were wrong but you just confirmed what I paid someone to diagnose. Guess I will have to decide as it is an old car and did last quite sometime (had it since 1990 in the family).

 

Yes on these cars that saying; "if you own an old Mercedes you are either Rich or a Mechanic" seems to ring true.

At least you got a lot of use out of the Car.

Some would consider 260,000 not to be a lot of miles. If you advertise on seveal of the different Mercedes Forums it might be you could get more for the car than if you junked it.

If you wanted to keep the Car it would be better to find another car that has a bad Bodoy or Transmission but but runs well enough for you to test the Engine and use that one for the souce of an Engine.
From what I have read buying a used Engine that is out of the Car and on a sitting on a Pallet with no way to test it about 1/2 the time turns out also to be a poor Engine. Sellers simply do not tell or do not know the true milager or as in your case of overheating what happend to the Engine.

 

Well, since it's a 87, I would personally rather buy a new car than changing it. It can be cheaper in the lenght, but you should ask some local mechanic at your place. I just know that in Norway that would be cheaper :-)

 

I may be interested in the tranny
87 300D
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