[Vwdiesel] '81 Rabbit overheating

[Terry Briggs]

The main reason for a 14psi cap is it stays below the 15psi limit of a 
low pressure system, get over 15 psi and the whole system needs to be 
certified as a pressure vessel . Our car cooling system is for a lack 
of a better term, a low pressure boiler. if it weren't that way, we 
could get some really good heat from our little diesels, then again, if 
the system overheated, the resulting steam explosion would most likely 
total the car I should think.
On Dec 20, 2007, at 5:36 AM, William J Toensing wrote:

> 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.
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