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I don't know the operating pressure of temperature of your car but it will work but maybe not ideal. Every 1 lb. difference on your cap will have about a 3 degree effect on the boiling point, so if you went to the 13 lb. cap your coolant would boil about 6 degrees lower. If you go higher pressure your boiling point goes higher but the extra pressure is harder on your hoses. In the end I wasn't any more helpful than the parts store but at least gave you something to think about.
I don't know the operating pressure of temperature of your car but it will work but maybe not ideal. Every 1 lb. difference on your cap will have about a 3 degree effect on the boiling point, so if you went to the 13 lb. cap your coolant would boil about 6 degrees lower. If you go higher pressure your boiling point goes higher but the extra pressure is harder on your hoses. In the end I wasn't any more helpful than the parts store but at least gave you something to think about.
You know it really doesn't get over 185. Maybe 190 at a stop light. The things only ever ran hot once and that's because I didn't have a spring in the lower rad hose.
Your original cap would have been 15lb cap ether an RC-15 copper/brass radiator or an RC-26 aluminum. Later RC-15 Stainless Steel cap would work for ether style radiator. You can sometimes find the stainless steel caps on ebay for $20 to $50. But the cap listed here should work.
Took your advice, looked it up myself found the cap and part #. Went to the store.... 7.7l ? 3 carbs? What vin? 4x4? Auto or manual etc .... Came back with that 13lb cap... Told them the part number I found online..... Got it!
Took your advice, looked it up myself found the cap and part #. Went to the store.... 7.7l ? 3 carbs? What vin? 4x4? Auto or manual etc .... Came back with that 13lb cap... Told them the part number I found online..... Got it!
I know, some questions are ridiculous. I inquired about a rear transmission seal, automatic, 71 GTO and was asked if it was a diesel.
Curious what you are trying to accomplish with a 13psi cap rather than the recommended 15psi cap that came from the factory?
Well I'm chasing down a problem. My car spewed it's coolant on Sunday. Now the cars got a rebuilt motor, new Edelbrock water pump, new high flow thermostat. It's a 68 big block but does have an expansion tank. Last few times I've driven it it bubbles over into the expansion tank. It's at 185 degrees both on the gauge and infrared gun.... Thought I'd start by burping it.... nothing. So now my next thought is radiator cap. I bought a 15lb cap. Next I'll be doing a combustion test with this doohickey from harbor freight
Well I'm chasing down a problem. My car spewed it's coolant on Sunday. Now the cars got a rebuilt motor, new Edelbrock water pump, new high flow thermostat. It's a 68 big block but does have an expansion tank. Last few times I've driven it it bubbles over into the expansion tank. It's at 185 degrees both on the gauge and infrared gun.... Thought I'd start by burping it.... nothing. So now my next thought is radiator cap. I bought a 15lb cap. Next I'll be doing a combustion test with this doohickey from harbor freight
Just to be clear the cap is being installed on the expansion tank? You dont have a cap on the radiator and the expansion tank?
Radiator cap
