Logo
FULL SITE MENU

Not sure what pressure cap I need for my heat exchanger.

B

briang0

Regular Contributor
I have a Crusader 1964 CS280 409 ci that is 1/2 fresh water cooled. I notice recently a little antifreeze coming out of the overflow tube especially after I top off the tank. The cap is old and very rusty and I cannot see any numbers on the cap. Does anyone know what PSI rating of the cap I should get? The only number I can see on the cap is in the center and it appears to be "7" The engine is running well and the temp is constant but I don't like to have antifreeze going into the bilge. I have an owners manual and a service manual and I have not been able to find any mention of the psi rating.
 
You may want to install a coolant recovery system.
If so, then you want a double sealing cap (intended for a recovery system) that provides both mild pressure for the "Closed Cooling" system (I believe 12 psi max, if memory serves me), yet offers a good seal at the top of the neck, so that coolant can be drawn back into the H/E during cool down.

Wrong cap, and this cool down cycle will not cause any coolant recovery from the reservoir!

.
 
I know they are different engines, but my 1990 454s have 7 psi caps along with the recovery/expansion tanks. In the dead of winter when on the hard all the antifreeze gets drawn into the engine, but in the summer when they are hot the level is about 2/3rds full, which tells me it is working properly.
 
I'd bet the cap is rated at 7 psi...they were standard when I went to factory school and that was late 70's vintage. Most things didn't change until fuel blends changed and induction systems started straying from carbs (thanks EPA).
 
Back
Top