PeachParts Mercedes-Benz Forum - View Single Post

Richard Wooldridge · #6 04-11-2007, 01:06 AM

Hi Roncallo,
I vote for the water pump, or possibly the thermostat to lower hose housing leaking at the thermostat side.
I just replaced the water pump on my '82 380SL that has the 560SL engine installed last weekend. It had a somewhat similar leak, in that I never did figure out where it was leaking, but replacing the water pump fixed it. When I removed the pump on my engine, I discovered that the pump had been previously replaced, and whoever did it never used a gasket, but only used some silicon sealant, and it didn't do the job- water had gotten to over half the water pump securing screws and rusted them very badly. In fact that may have been the problem, I just cannot say for sure. To remove the pump you must pull the crankshaft harmonic balancer/pulley assembly out about an inch for clearance. (27mm socket) It is a very good time to replace all the belts, since you have to take them all off anyway. Also a good time to replace the hoses. I discovered that the flashing on the inside of the thermostat - lower hose housing was not allowing the thermostat to fit properly into the housing, so used a die grinder to carefully smooth the inside enough for the thermostat to fit properly, thus allowing the housing to go all the way up to the water pump itself, compressing the O-ring properly. When I reassembled the unit, I put grease on all the bolts so that they wouldn't rust up again.