I was losing some coolant over a period of time. The car temp was around 82Centigrade, no overheating. I found a slow leak around the thermostat housing. Changed the thermostat, and that solved the problem.

The job was fairly easy. No need to jackup the car.

1) drain the coolant
2) take off rubber pipe that connects the air filter housing to the Turbo.
3) disconect pipe ( that runs from rubber pipe to top of cam cover )
4) take off thermostat housing. There r 2 bolts (10 Nm)
5) pull thermostat housing with lower radiator hose towards u. Clean thermostat housing. there was some driedup coolant which I scrapped off with a flat head screw driver.
6) there is metal point on the housing that fits a slot on the thermostat.
7) Button up, fill up with coolant. Put heat on high, depress defrost button, take for a spin.
8) Check coolant level after a 1/4 mile. Top up accordingly.

Hope this was helpful.

If you drained the radiator but not the block, was there coolant held back by the closed thermostat? None, a cupful, Niagara Falls?

Sixto
93 300SD 3.0

I got about a gallon or so out. I did not drain the block - should have.

The rubber gasket on the old thermostat had seen better days.