Wife complained that the 1990 300e (215K) was runnig a little hot with the a/c on. Well she's right. I've searched various threads and found some answers but not all. The biggest thing that concerns me is that the engine coolant reservoir looks like it has engine oil in it. The appearance is foamy brownish milky looking(real tech talk hear!). The engine does use about a quart and a half bt. 3000 mile oil changes, but have not seen fouling of the plugs. Can this be possible?

If there is oil in the coolant then I would suspect the headgasket has failed. You probably will also have an oil leak toward the back of the engine on the right side closest to the firewall. This is very common on the m103 engine with this type of miles if the headgasket has not been replaced. Hope this helps

I concur with givan or whatever his name is. You need a headgasket minimum, but at that mileage I recommend a valve job.

Peter

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Auto Zentral Ltd.

I had a head gaket failure on a Toyota years ago and the coolant went into the cylinders. The car runs well other than the obvious at this point. Can I confirm this myself at home and also with this kind of milage on it, if I go ahead with the suggested repairs what kind of additional mileage can be expected from the bottom half. I realize that this is a tough question.
Thanks again

With regular oil changes, the bottom end will last about forever.

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1989 300 SEL that mostly works, but needs TLC

One more concern that I have at this point is did the overheating cause the failure of the head gasket or did the failure cause the overheating. I don't want a repeat. I live in maryland, can anyone ballpark the $$$ of this repair if a shop does it. I read a post by blueranger that is going through a similar project and is doing the repair himself. The guidance from fellow board members seems to be helping him through it, but the last post on that thread makes referance to it being done wrong.

My head gasket experience is with a M104 engine, 130k. The engine overheated with a failed thermostat and 2-3 months later I had the first signs of oil in the coolant tank. The repair was about $1700. Add more if your water pump is about due. My tech said fixing this sooner is better than later as the oil deteriorates all the rubber hoses in the cooling system.

glenmore
1991 300CE
1990 LS400
2000 C280