hey guys, going shopping for a new radiator cap for my total stock 53 ford customline with the v8. im wondering what lb cap i should run? ive been seeing ppl post about overheating and having it end up being a radiator cap problem. so i want to make sure i get the right one. tia tim
OK, 8 hrs is enough. I'll bite. ***uming you have no sealing issues and your motor will hold pressure, use anything between about 7 and 16 psi. The higher the pressure, he greater a temp you can handle without boil over. Best combustion is above 185* oil temp, so don't wuss out and run a 160* thermostat. Get up to operating temp. If your cooling system has adequate efficiency, it will stay in operating range in the hottest weather. Just remember, 220* is not over heated. that is high end of normal on a carb and nominal in EFI motors. 240* is hot. If you have problems with vapor lock from fuel boil, that's a seperate issue. Did I forget anything? Now watch this thread take off....
I was in need of a new cap, kinda in a hurry and the store only had an 8 or 19, so I got the 19 and two days later the back seal on the water pump started leaking.(related? maybe?) I see some guys with "race cars" running really high pressure caps but is there a point where its too high for a street car?
I was always under the impression that 16 pound caps on V-8's were pretty much the norm for "most" cars made after 1965 (with an overflow tank)...up 'till the F.I. era... 16# is what I run in all mine...never had a problem...yet...
7 lbs is about all the mid-'50s and earlier radiators can stand due to design. I've had good success adding an upper gasket to older 4 - 7 lb caps, and an overflow catch can - no more coolant loss during hot weather.
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