91 up closed cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

91 up open cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

An OEM radiator cap for the open cooling system is rated at 16 psi, but 13 psi is the parts listing everywhere. Advance, Autozone and Napa all list 13 psi. Even Stant lists 13 psi. What's anyone's guess?

My only guess is this 13 psi cap is made for cheap-ass, plastic capped, aluminum core radiators, which can't take the pressure like a brass/copper soldered radiator.

They can't ALL have the same misprinted part specs. The Jeep "cooling system system normally operates at 97-to-124 kPa (14-to-18 psi) pressure."

Re: 91 up closed cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

look down about 10 posts

http://naxja.org/forum/showthread.php?t=933541

Re: 91 up closed cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

closed cooling systems dont have a rad cap....they have a pressure cap that screws onto the pressure bottle....the open cooling system has a rad cap...i use the 13psi on and have no problems on mine

oops, my bad. I meant open system, not the Renix closed system with the famous grenading coolant bottle.

Re: 91 up closed cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

Cuz they sucks.

Re: 91 up closed cooling system, 14-18 psi, Why do parts stores list rad caps at 13 psi?

always had a 16, never had a problem.