radiator cap

[Cooke]

I can only find 7lb. radiator caps at local stores, will this be OK to use on a 38, 60S? It has 4lb now but needs a new one. Thanks, Martin

[joeceretti]

I had a 7lb and my rad guy said, "that's what has caused that pinhole." He had a 4lb in his stock and he charged me $10. If you have a dedicated radiator repair shop around. Head there.

[Bill Ingler #7799]

The A/C cap was the correct cap used on the Cadillac. The correct cap number for the 38 Cadillac is RC-4 which is a 4 lb cap. Regardless of what brand name cap you use, it is very important that the cap length fits the neck length of the radiator or you defeat the purpose of the pressure cap.  Bill

[Richardonly]

Bill is correct.  If the seal isn't formed by having a long enough cap, air gets in, boiling and evaporation lets the coolant out.

Richard

[joeceretti]

When I had a 7lb cap on mine (It was there when I got the car) I was losing coolant constantly. I installed a coolant reservoir inside the fender with a rubber hose so I could reuse the coolant and not pollute the environment with my hard earned dollars. Since putting the 4lb on the reservoir never has any coolant in it at all.