which cap should I used?/my ford shop manual saids that the cooling sys is pressurized to 6 1/4 to 7 3/4 pounds/but the part store book calls for a 13 lb cap which is right? This is on a 55 fairlane 292 with a stock rad

I would go with the low pressure one.If your rad is old or original the 13 lb may be too much pressure.

  

Although the ’55 parts manual does call for a 12-15 lb cap, the stock ’55-56 radiators will give fewer problems with the 7 lb cap being used.  The soldered seam on the radiator tank simply doesn’t like the higher pressures generated with the 13 lb caps.  I went with the 7 lb cap on my ’55 Customline a couple of decades ago with absolutely no heating issues and radiator problems went away as a result.

Lorena, Texas (South of Waco)

My 56 manual shows 13 PSI. I have a new radiator and the cap I am using only comes in 7 or 16 PSI. Am I ok using the 16? Mike

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Yellowing, I would go with the 7lb., 16lb is too high.

BOB

Wouldnt a 13 or 16 lb cap increase the possiblity of coolant leaks at head gaskets, timing cover and/or intake?  I have an aluminum rad made for race use, but still use the lighter 7lb. cap.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

The Ford parts catalogue and the quick reference book call for a 12-15 pound cap in 55+.The 7 pound cap is listed for 52-54.I would asume the higher rated cap is used to raise the boiling point of the coolant.You can use either cap if your rad,heater core and gaskets are in good shape.If you want to be sure use the 7lb cap.

  

I ran a 13 lb cap for a while and was constantly blowing out the seam in the top tank. Switched to a 7lb cap and no problems since, either with leaks or overheating.

thanks for all the info Im going to used the 7 lb cap I don't what to blown a rad or heater core