basic questions--cooling system E39
 

On Tue, 14 Sep 2004 10:17:23 -0400, md wrote:

> My 1997 540i at about 150k miles seems to be acting up lately.
>
> BUT TODAY, the 'Check Cooling Level' indicator went on. I had recently
> had water pump and hoses replaced. When I went to open the radiator
> (engine heat was fine when i drove it to work), instead of being LOW on
> coolant, when i opened the cap, coolant came pouring out (it had been
> stopped for about 15 min) Why would coolant level be too high and not too
> low? The radiator water pump problem was about 4-5 months ago and nothing
> has happened since. Air temp today is about 75 degrees F, so not a hot or
> cold day. Could this be a stuck thermostat? What would cause this?
>
From the darker side... One thing that can cause this is a bad head gasket
that's leaking from a cylinder into the cooling system. What happens then
is that the system will hit over pressure while being driven and vent
coolant out the overflow. Then when you stop the "Low Coolant" switch
trips. Opening the cap releases the pressure and the gas bubble in the
system causes coolant to fountain out.

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The instructions said to use Windows 98 or better, so I installed RedHat.