My radiator cap is marked as being 13lbs, but I'm finding that it's pushing some water out, is 13lbs correct or should I be using something higher? Engine is a 302 Windsor, stock radiator.
Thanks
I would think that is more than sufficient. I am thinking maybe thermal expansion is the culprit and it will stop at some level. Steam would not overpressure the system until the temp reaches 245 degrees F.
Gary, somebody will have to confirm this, but I recall a stock radiator as having a suggested cap pressure of 7 lbs to keep higher pressures from rupturing the tank. With that said, I ran a 7 lb on my new aluminum radiator, but found that it was spitting coolant over the top of the engine, so I switched to a 13 lb and have had no issues since. My aluminum radiator is welded though, not brazed as the oems are.
Whenever I ran a 13 lb cap on my stock radiator, it was always springing a leak at the top tank. Dropped it to a 7 lb cap, fine ever since.
Sometime over the years the depth of the neck changed, I don't have access to my original radiator to check it's up in the rafters. I remember trying a later higher pressure cap on some early radiator and it didn't seal. I could fill the radiator and squeeze the radiator hose and it would spit out the overflow because it didn't seal..