Here is the update to my leaking thermostat. and its not good.

[The car is a '95 E300 Diesel].

I took the car to my mechanic this morning complaining of a leaking thermostat. What was supposed to be a straight forward job of changing the leaking thermostat and its associated O ring, is now turning out to be a complex and expensive proposition. When the mechanic (Who I fully trust) removed my old thermostat he noticed that the Aluminium housing that the thermostat fits into (the housing on the block side not on the hose side) is severely pitted.

He tried to use a bit of "gasket maker" before he put the new thermostat and O ring back in but as soon as he filled up the car with antifreeze it started leaking again. That's before he even started the engine.

He now says that this may end-up being a big and expensive problem to deal with as he may have to order and change the thermostat housing on the block. This part has to be ordered from Germany as Mercedes does not stock it locally, and may take 2-3 weeks to arrive. Not to mention the additional labour involved in removing and installing this housing.

He hopes that perhaps JB-Weld could be used to fill in the pits in the aluminium housing, and then once dry and sanded, should seal again as good as new. I left the car there till tomorrow morning as JB Weld specifies 16-Hrs. drying time.

Has anyone ever experienced such a failure before. Could JB Weld do the trick? Any other ideas or tricks if JB-Weld fails to seal the pits in the aluminium?

Thanks

Phil