560SL Small Coolent Leak

[Roncallo]

I have a small amount of coolent driping from the right front of my 1988 560SL. It appeares to be comming out of the 2 front right hand side oil pan to block screws. The front most screw is located about 3 inches directly below the block drain plug but the drain plug is clearly visible and absolutly dry. Visibility in the water pump area is very limited and I cannot see the gasket or if there is a drain hole like most water pumps have on the bottom of the shaft extension. I can remove the oil filter to get a better look but I'm trying to avoid that for the moment. Has anyone seen this.

John Roncallo

[Strife]

It's really hard to see the beginnings of a water pump leak, but that's probably what it is. Another sign is (assuming that you are using the MB coolant) are the dried stains all over the crank pulley and on the alternator and support arm from the thrown coolant.

[Roncallo]

So far my guess is water pump. I dont see any stains yet but it's still a very small leak. I am using MB coolent.

Thanks for the tip, I will keep looking
John Roncallo

[page62]

A packet of Aluma-Seal won't hurt (other "stop leak" products might). It seals the pinholes, and actually lubricates that failing water pump of yours....

[irinesroger]

The thermostat housing is located on the left hand side as you look at the motor, sometimes the bottom of the three bolts that hold the housing to the water pump will come loose or it may be stripped as mine is. Remove and use a good silicone sealer and IF that is the leak it shold be stopped.

[Richard Wooldridge]

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.

[Richard Wooldridge]

Hi Roncallo,
I'm wondering what you found on your leak? Or, did you just put some alumaseal in it? Or, are you not driving it right now?