1966 230SL Coolant Leak

[Harry]

This one really has me going.  I have just a dribble of a coolant leak that is present as a small spot behind the driver's side front wheel.  Under the hood, the "shelf" beneath the brake booster is wet.  I feared the heater core may have a leak except for two things - the core was recently rebuilt and tested, and the core really sets in a framework above the fan assembly.  I can't determine a flow path from the heater core to the shelf.  It would seem that a leaking core could only reveal itself through the fan assembly.  Is that not correct?

The counter argument is that I can find no coolant lines in the vicinity of the brake booster.  I pulled the rubber access plug for the valve on top of the core but saw no indication of any coolant.  I'll do that again and look harder.  In the meanwhile, if there's any experience or similar problems, I would appreciate the advice.

Thanks very much,
Harry

[Rolf-Dieter ✝︎]

Hello Harry,

You point out that the leak is "a small spot behind the driver's side front wheel" As you know it is difficult to tell where the leak originates. The leak may be anywhere up front and as we drive our car it moves (the coolant leak) back and/or sideways. Unless you already have done so I would recommend to carefully check all hoses that are part of the cooling system at the 6 oClock (lower area) for wet spots in order to find and trace the likely leak. Include of course the thermostat housing and the radiator.

I had 2 cooling leaks one was from a lower half housing horizontal joint of my thermostat (poor joint condition pitting) and the other was from the radiator (directly in line with the tow hook) it was damaged by the tow truck operator when my car had to be towed last fall.

Good luck, I'm sure you will find it some white gloves will be of help

[George Des]

Are you sure this is coolant and not windshield cleaner fluid? The only thing in that area with fluid is the cleaner bag, pump and reservoirs for cluth and brakes.

[Harry]

I thought the same on the windshield washer bag but its not leaking, and its definitely antifeeze I am seeing.  Just got back from a ride in the card and I'm going to look again.  I definitely do not see or smell any leaks through the access hole over the heater core.  Thanks very much for your ideas/suggestions.  I'll share what I learn.