Originally Posted by JohnM.

Headgaskets on these cars are vary rarely the cause of overheating. 9/10 times the failure on original head gaskets is between a coolant and oil passage. And its usually oil into coolant system contamination. But this doesn't cause overheating. Bad water pump, clogged radiator, bad thermostat, and the use of non-MB coolant over an extended period of time is more likely the culprit when it comes to overheating.

If they replaced the head gasket because it was overheating, and it's overheating again because of the HG. They most likely did it WRONG. The new head gaskets are already reinforced in the weak areas and should be good for the life of the engine after you do it once. The stock HG is also good for up to about ~300HP according to the turbo'd crowd.

You also still see many 300E's running around on the original head gasket. But they are one engine overheat (120C) away from needing replacement! A lot of the 300E's for sale with bad HG's also have new radiators Because the original plastic necked radiator busted (usually on the highway) and the engine overheated. New radiator, and then there's an fancy new oil slick in the coolant overflow bottle!

Why you see so many cheap ones is because unfortunately they have hit the bottom of the depreciation curve, for now. It's getting very hard to find a nice one because people are just driving them into the ground and throwing away the keys. No need to maintain it, or check fluids or do anything to it. Because it's a "Benz" and they can take it. They can take it. But it sure does leave 'em all dried up and nasty...