Coolant Leak Mystery 92 500sel
 

Hmmm. So, it all started when I decided to check the water level, and then drove off without putting on the radiator cap. I only drove a couple miles, and when I stopped there was lots of water running out, and I realized what I had done, so I waited a few hours and then refilled it and drove off (hoping it was all normal, but it wasn't...)

Now, it acts weird. It seems to leak a little coolant most times when I stop the car.

Yesterday, I drove 100 miles under varied conditions. When I stopped, it didn't leak. Then I drove another 50 miles, varied (hiway and city), and when I stopped, no leak. Then I drove 3 miles, and when I stopped it dropped a quart of coolant.

It seems that if I drive extended periods, it works fine. Short distances cause it to spit up.

It doesn't seem to spit up when running, regardless of conditions.

Yes, I have tried to bleed it when filling (putting it on a hill, running the heater, etc.).

Any help or guidance (or guesses...)...

Thanks

-David
92 500sel
86 560sel
85 535i
82 QPorte

Replace the . . .
 

pressure cap! It must be leaking and not maintaining the required pressure.

Also 'burp' the upper radiator hose to make sure that there's no trapped air. The 140 cars don't usually trap air but anyting is possible!

Problem Fixed!!!!
 

Ok, so here is the important question - is the car overheating, and therefore boiling over - OR - is the system leaking, which doesn't allow it to maintain pressure, and then subsequently overheating and boiling over.

IT WAS LEAKING! There was a pin hole in the cooling hose that goes from the water pump down into the fan housing (90degree 4" long hose). This was leaking (only under certain conditions, but definitely when the car was turned off after a short drive) and then allowing it to overheat and spill (in addition to the small amount coming out of the leak).

I replaced this hose last night, and have seen no leaks or problems since. :)

Thanks for everyone's help.

-David
92 500sel
86 560sel
85 535i
82 Qporte