Pressure or nonpressure

while we have lift unit off also have pulled off radiator and had it cleaned and checked due to 2 inches of gunk in bottom of housing. radiator cap is shot, now needing to replace can any one tell me which type to use, Pressure or nonpressure.
this is a 1964 cup.

Non pressure type. Fluid will find it's level (approx. 2 inches below cap) after boiling over. This type system (thermosiphon action) operates better with the non pressure cap.

Some later Cubs had a pressure cap. I haven't been able to find any indication of when the change was made. Your tractor should be fine either way.

Thank for the information. everyone is eager to help outher when we can't find the correct prat.

cccub:

Having fun with my new catalogue..

If your cap just needs the gasket then order Part # 351030R91

If you want the old style non-pressurized cap then that is Part# 351030R91
which is replaced Part #400584R1. If I remember correctly when I got mine the replacement is actually a pressure cap. If you want the original, you will have to find someone with NOS.

I think my dealer said the gasket was still available for the old style cap is you want to rehabilitate yours.

Jamie, over at JP Tractor, supplied me with a non pressure cap, good used. 573-783-7055