Re: Overheating Woes

[ChuckKuecker <ckuecker@mcs.net>]

At 21:09 8/5/97 -0700, you wrote:
>  Maybe your water pump isn't working up to par? Or maybe your system is 
>developing too little/much pressure? I've had a pressure cap go bad, causing 
>overheating due to excessive pressure on the cooling system. It would overheat 
>after a few miles of driving, but the fan appeared to be working, the
thermostat
>appeared to be working, and the system had been recently flushed and filled
>with VW antifreeze and distilled water.
>
>Brad

Nitpick time - if the pressure cap is NOT holding pressure, you get an
overheat. The only thing that a cap that hold TOO much pressure will give
you is blown hoses if your fan quits and the car keeps heating up. 

The pressure cap causes the boiling point of the coolant to be higher than
if you had it at atmospheric pressure. If you run with the cap off, you will
boil the engine dry quickly at 212 F. With the cap, the boiling point is
more like 250 - 275 F. Also, the coolant can carry more heat at the higher
pressure, so better cooling. 

Check to see if the cap is holding the proper pressure. When they fail, it's
ususally on the low side - and you boil over real easy.

Chuck Kuecker

ckuecker@mcs.net

'83 Scirocco (new paint!)
'58 Ghia Convert
'75 Bug (getting better)
'67 Bug
'63 Bug (for sale)
'91 Vanagon


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