41-48 A/C Radiator Caps

[Bill Ingler #7799]

For those of you who drive a 41-48 and are using the correct RC-7 cap, you know these caps are getting hard to find as well as expensive. A word of caution on storing your car for long periods of time without running the engine and what happened to my radiator cap. Before starting my 47 which had been in storage for 5 months and not started, I removed the radiator cap to check the level of coolant and part of the bottom rubber sealing ring on the cap stayed stuck to the neck flange of the radiator. Fortunately I have a spare cap but in the future if the car will sit for several months, I will loosen the radiator cap enough so it is not ridding tight on the radiator neck flange.  So if you have or buy even a NOS cap, remember the weak point of these caps is the age of that rubber sealing ring.   Bill

[Bobby B]

Bill,
   Thanks for the "tip" and a little reminder regarding that issue….I have an NOS cap on mine. They are not cheap.
                                                                Bobby

[joeceretti]

Funny story. I had a devil of a time finding the right 4lb cap for mine. I went to have my rad rebuilt at a really old rad shop a few blocks from my house, now being run by the son... first thing he said.. that's the wrong cap... reached over to his work bench.. rustled around for 5 seconds and handed me the right cap.

He rebuilt my rad. It is a work of art. It wasn't cheap but certainly not expensive for what I got. When it was recored at some point in the past it was made about 1/4 inch too tall. To solve the problem someone had jammed cut up chunks of tires between the cowl and the rad to keep the cowl from cutting through it. Not the best of solutions. Also, the rad was about 60% of the thickness it should have been. Overheating was a constant problem.

With Bill's advice I think I will go and see if he has another cap.