Radiator Cap Pressure Rating?

[BillCA63R1]

The aftermarket cap on my radiator 'Header' tank is stamped "16" pounds. Is this acceptable or is 14 pounds correct? Is this a critical function?

Bill

[avantifred]

Hey Bill, The shop book says 13#..........Jon Meyer sells 14# and I have NO PROBLEMS. The book, "What the (Avanti) shop manual won't tell you" ( by Stan Gundry) suggests using a 7# cap to make it a little safer for the radiator & expansion tank........you decide; is your cooling system up to par??!

[BillCA63R1]

The cooling system on my R1 has had a LOT of work done on it. I now have a 195 degree thermostat and the car seems to run quite happily with the water temperature between 195-210. What I HAVE noticed is that the fluid level in the plastic overflow tank does not show any change as the engine warms up to full operating tempurature. It is as though the radiator and header tank are functioning as a strictly closed system.

I assume that one effect of having a 16 pound cap is to cause the cooling system running at a higher pressure, thus raising the boiling point (temperature) of the coolant itself. For this reason I am hesitant to lower the pressure rating of the cap.