W201 Coolant Leak
 

My '92 190E (2.3) has developed a significant collant leak. It appears to be coming from rear of the engine, so I immediately thought that it must be a heater hose -- but the heater hoses are fine. In fact, all the hoses seem to be fine.

When I let the car idle in the driveway, it doesn't leak. It also doesn't seem to leak when I drive it. But after I park it (after dirving) and it sits for a minute, then the leak starts.

Where should I be looking??? Any insight is appreciated.

Thanks in advance.

Jeff Pierce

Did you remove the plastic HVAC plenum screen and check the hose connections and heater control valve? Leaks in this area will usually drip through the plenum drain and land on the transmission.

Carefully check around the auxillary coolant pump. Sooner or later they will begin to seep.

Also, don't overlook the coolant pump and hose connections up front. Small leaks often migrate along the engine and drip at the back even though the source is up front.

Duke

Thanks for the suggestions, Duke. I'll check them out.

Jeff Pierce

Borrow a pressure testor from one of the stores like AutoZone.
It is a fact that the pressure builds after a hot engine is shut off and will like a few minutes later. It is difficult to look around for leaks on a hot engine. The pressure tester will let you do so repeatedly when the engine is could.