Coolant Level Drop: Thoughts, Concerns? - Page 3 - PeachParts Mercedes-Benz Forum

shertex · #31 11-12-2010, 07:13 AM

Quote:

Originally Posted by punkinfair

i had a similar issue with my '87 TD. the overflow tank had a very small crack in it and the fluid was leaking out. it would only leak when the engine was hot and when it leaked the amount of the leak was very small, so that the liquid never made it to the ground, it evaporated or dried up before making it to the ground. perhaps a small amount made it all the way down to the ground but i never noticed it, like there was never even a small puddle. the fluid leaked in a way that you could not see any fluid on the bodywork of the engine bay, it was hidden from easy view. once the fluid level fell below the level of the crack, the leak would stop, that was the other mystery. the only way i discovered the crack was by removing the overflow reservoir and looking at the underside of it. i was almost sure there was something wrong with the engine internally because it seemed to be the only explanation for the behavior. i ordered the oil analysis kit and everything. luckily i was dead wrong and a new reservoir was all the was needed.

I'm going to continue to monitor it closely. If this is in fact the problem, I wonder how low the coolant could go. I assume just slightly below the seam.

shertex · #32 11-12-2010, 12:52 PM

New related post/question, but thought I'd copy here:

If Coolant Overflow System Leaking, How Low Will Coolant Go?

If Coolant Overflow System Leaking, How Low Will Coolant Go?

--------------------------------------------------------------------------------

As I have learned from a number of you, my car (1992 300D) has a coolant overflow reservoir. Overflow coolant goes into this tank when hot, then is sucked back into the the expansion tank when the system cools.

I strongly suspect that this system (either hose or tank) is leaking and that that accounts for my loss of coolant. The reason I suspect this is that the loss rate has substantially decreased as the coolant level when cold has approached the seam in the expansion tank. Currently the level looks to be about 1/8" inch below the seam.

My question: how low would the cold level have to get before I could conclude that the overflow system is NOT the problem?

Thanks.

Olivier · #33 11-12-2010, 01:02 PM

I had a nightmare to fing a teeny leak as well, it was the water pump. Under pressure it was loosing a bit of coolant, as mentiooned above, it was so small that it evaporated right away and it was hard to find.
One day I was under the car whith the engine hot and running and got a drip from the pump "tube". This was it. I thought it was the cap of the reservoir, the piping, the reservoir, anything, it was the pump.
You might want to have a look into it?
Olivier

shertex · #34 11-12-2010, 01:06 PM

Quote:

Originally Posted by Olivier

I had a nightmare to fing a teeny leak as well, it was the water pump. Under pressure it was loosing a bit of coolant, as mentiooned above, it was so small that it evaporated right away and it was hard to find.
One day I was under the car whith the engine hot and running and got a drip from the pump "tube". This was it. I thought it was the cap of the reservoir, the piping, the reservoir, anything, it was the pump.
You might want to have a look into it?
Olivier

I definitely will....thanks. But I would think that, if it were anything other than the overflow system, the rate of loss would remain constant.

Olivier · #35 11-12-2010, 01:13 PM

It was not for me. It was really tricky to get it. I even thought I needed a head job... Expensive. It was the pump.
The bearing I was told work under pressure, this is why I could never see it, I needed to have the car really hot and be under to get it. It was after more then a month or two after the first warning, then I guess it was getting a little worse bit by bit.