Strange Coolant Leak from 83' W123??
 

Hear is the deal, I am a proud owner of a 1983' 300D Turbo with 115k on the clock (Faith). I recently went out to crank her up for my daily commute to school and noticed a rather large pile of the green stuff under her. I checked the expansion tank, completely empty! I refilled it and watched for leaks, nothing visible. It seemed to be leaking off something above the oil pan, probably around the thermostat. I squeezed the upper radiator hose and noticed a lack of fluid and pressure. I drove the car for a day or two a noticed that the level in the expansion tank had not chanced. Later, I figured out that it would only leak when the climate control system had been used. I also have noticed the my aux. water pump is not working, So should I experience a lack in pressure through out the system if this pump is not operable? my impression was that the main water pump was responsible for primary circulation? I also am wondering if this pump is bad as well?, I really have no clue how to check for this, but I know that she has not been overheating when I drive her for extended periods of time, so I hope I'm not torturing her by continuing to drive will I find a solution. Any help would be greatly appreciated.

Drips from the oil pan are typically from the weep hole in the water pump. Close inspection will usually reveal a stain from the hole.
Unplug your auxilliary pump if it's not working. A failed pump can take out the climate control amplifier.
I can't account for why the leak is only occurring when the climate control is used.

Leaking monovalve?

Can you explain?
 

Kerry. Can you explain your post a bit more? Are you saying a failed auxillary pump can disable the climate control amplifier? What is a climate control amplifier? And what does all of this have with the weep hole in the water pump? Is the weep hole suppose to be plugged?

A stuck auxialliary pump can draw enough current to fry the climate control amp which I believe is in the vicinity of the glove compartment. It doesn't have anything to do with the weep hole. I only mentioned it because the amp is not cheap so you don't want it to fail.
Weep hole should not weep and is always open. It weeps when the water pump seals fail. It's on the bottom of the pump.

Might be...
 

I just went through some weird leak problem. I thought it was a hose at the bottom, that's as high up as I could detect the leak. Bought the hose, took it to a mechanic, thank God, because he found the radiator was leaking. Had to get a new one of those.

jeff

What is a good sized fuse to put into that circuit?