I have a '90 that has been blowing cooling system parts (Transmission
coolers, rear heater cores, etc.) The general feeling is that
compression from the cylinders is leaking into the cooling system,
causing excessive pressure.

I pulled the spark plugs to look for the offending cylinder. The
picture on my web site shows the four plugs:

http://www.phonyexpress.com/images/sparkplugs.jpg

The ceramic on Number 2 (at the far right in the picture) spark plug
is very clean compared to the brown look of the others, while there
is a lot of buildup on the metal (brownish white), which might
suggest corrosion from the moisture here, while the clean ceramic
comes from coolant in the cylinder. Am I reading this right????

The car has 188,000 miles. Even if it is just one cylinder creating
the pressure problem, would everyone concur that a complete rebuild
is the way to go vs. just fixing the one cylinder?

Thanks for your advice!

Paul In Columbus, Ohio

Pictures of my Vanagons:

http://www.phonyexpress.com/images/VWs.jpg
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'90 Vanagon (180k)
'84 Vanagon (217k)
'78 Microbus (175k)