Pressurized Radiator
 

I visited a club member this evening who is installing a new touring engine from AER and a 4 speed transmission. He also ordered a new aluminum radiator for the Model A with the recovery tank designed to be pressurized. The radiator cap that came with it looked of lesser quality and did not have a pressure rating on it. I suggested he make the call to find out the caps pressure rating. This got me thinking, what psi cap should be used when one chooses to pressurize? Of course he doesn’t really need a hopped up cooling system, but since he can and he is having fun, it’s going to be a pressure system.

Re: Pressurized Radiator
 

If I remember right, the boiling point of water is 243deg F at 16 psi. That may be the number for a coolant mixture.

Re: Pressurized Radiator
 

My only thought is that Model A water pumps leak enough without pressure.

Charlie Stephens

Re: Pressurized Radiator
 

I see a couple potential issues with a pressurized system, the waterpump and the head gasket.

That being said, I run 4# pressure cap, V8 model pump for the seal and pray for the head gasket. Not really, ARP studs properly torqued and Serr/Miller OHV head.

As with anything, if the motor is in good repair, it will not be an issue.
If not maintained within reason, it will fail, leak, or just be a PIA.

John

Re: Pressurized Radiator
 

I run a pressurized system with a sealed water pump. No problems.

Re: Pressurized Radiator
 

I do also on two of my cars with a 4# cap.
Good Day!

Re: Pressurized Radiator
 

Other than increased boiling point, what is the purpose of a pressurized system.

Re: Pressurized Radiator
 

Use a 4lb cap

Re: Pressurized Radiator
 

JMO: With a sealed system, there is a coolant capture tank that holds the excess coolant when the system is very warm. I think the 4# cap seals better to the top of the radiator and then is better able to pull the coolant back into the radiator from the capture tank as the system cools.
Good Day!
Dave in MN

Re: Pressurized Radiator
 

Thanks for the input. I’ll relay to him the 4# cap.