Can too high PSI radiator cap cause overheating problems with regular water/coolant? I've been using the Blitz (18.5lbs)high pressure cap. I forgot what psi the stock cap is.

I was reading my Evens coolant instructions and it recomends a 7lb radiator cap but it shows boiling points at 0psi? Is there such a thing as zero psi cap? If you run a 7psi or even 18psi then does that reduce the boiling point? ...is their boiling point deceiving?

 

Either way a higher psi cap will raise the boiling point. With Evans, the boiling point is already so high there is no need for a high pressure cap, so many people run a low pressure cap, or modify a normal cap for 0psi (basically remove the rubber seal so it won't pressurize). An 18psi cap is fine for normal coolant, but unnecessary with Evans. Remember, higher pressures put more stress on the entire cooling system, so a rule of thumb is to use the lowest pressure that eliminates boiling.

 

Either way a higher psi cap will raise the boiling point. With Evans, the boiling point is already so high there is no need for a high pressure cap, so many people run a low pressure cap, or modify a normal cap for 0psi (basically remove the rubber seal so it won't pressurize). An 18psi cap is fine for normal coolant, but unnecessary with Evans. Remember, higher pressures put more stress on the entire cooling system, so a rule of thumb is to use the lowest pressure that eliminates boiling.