[Vwdiesel] '81 Rabbit overheating

[William J Toensing]

I thought I would wait to see if someone else would comment, but water boils at 212 F (100 C) at sea level. It boils at a lower temperature as altitude increases & air pressure decreases. As pressure increases, the boiling temperature increases. This is why modern cars use pressure radiator caps to increase normal operating temperature. This is why modern cars often use 14 pound pressure caps. Then the operating temperature can run much higher. This is why some temperature gages go up to 265 degrees F. There is a formula to figure how much the boiling point rises or lowers with a change in pressure, but I forget what it is.
I would suggest adding a remote temperature sensing unit with a laser beam you can point at the part of the cooling system, engine, or other part you might want to measure the temperature of. I bought one at Costco a few years for around $50 as I recall. Auto parts houses should have them too. Radio Shack has a cheaper one without a laser pointer for less & they might have one with a laser pointer too.