Rad cap search for "RAD 6375 5623"

[85Bears]

Dear all,

I am looking for any info on the radiator in my 1969 Charger 440. I bought the car with this aftermarket radiator so I have no idea of the history. It has nothing on it but for "RAD 6375 5623" on the driver side of the radiator. I am in search of the correct cap for this radiator as the ones at the parts store are not solving my issue.

My issue is the cap is not holding pressure (this cap is also a duralazt / auto zone one that was on the car). When the cap is on and you squeeze the top hose you can hear / see the overflow tank responding. My thought is that the incorrect cap is on and isn't long enough to go below the pin hole for overflow....

Any help would be awesome and much appreciated.

 

[kiwigtx]

Sounds like you might have a lot of air in the system....have you tried purging etc?

 

[85Bears]

Hi Kiwi. I flushed it about 10x. Twice with macs 1400 then about 8 times w distilled water. It was pretty dirty. After filled back up and tweaked concentrate / distilled water I just ran it and that’s it.

not sure how to get air out? Even if air is in there it shouldn’t go past the cap when the car is cold, right?