Rad Cap pressure setting

While pulling the alternator to get it repaired I was looking at the rad cap and was curious what pressure most people run? The things you think about while waiting for parts.

Well I found my answer. Turns out a 13lb rad cap is what I should be running and somewhere along the line a 22lb cap was put on. I was trying to sort out some cooling issues and sometimes you don't see the forest for the trees. I also swapped my thermostsat because I couldn't remember the last time I did it. I'll see if that solves the problems when I get my alternator re-installed, it turns out my fluctuating voltage readings were a couple burnt diodes and a bad voltage regulator on the PowerMaster alternator. Now just need some time to play.

I run a 22lb cap, raises boiling temp.

crittersf1 wrote:I run a 22lb cap, raises boiling temp.

yep

Agreed that's the benefit, I went back to basics so I could figure out what was going on. If I could only get enough free time to continue playing with the old girl

I believe mine is something like a 20#

I run a 7# on my mud truck, with the radiator mounted in the rear the hoses can get pushed off the pipes if you run to much pressure. I just soon the extra pressure go out the over flow then in my face. On the street I would stay around 13# if you need more to keep it from boiling then the coolant system needs attention some where else.

I use a Stant Racing Division 16 lb radiator cap.
If your coolant temperature gets anywhere near the boiling point of a 22 lb cap, you have a problem.

However, in a racing application (using a down-flow radiator), it is recommended to use a much higher lb cap,
because the cap is subjected to the hot side of cooling system pressure;
unlike a cross-flow radiator which has the cap on the cold side return.
http://www.stewartcomponents.com/Tech_Tips.htm

Thanks guys, great advice. I'll give feedback when I get some testing done.