• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

rad cap pressure rating

Share this page

T

twas_brillig

Jedi Knight
Country flag
Offline
We just did a camping trip in our BJ7 and I was losing up to 3 litres of rad fluid a day with no obvious leak; went over the Going to the Sun highway in Montana and left enough water tracks there to find that it was coming out of the rad overflow tube; went into NAPA in Kalispell and for about five bucks got the problem fixed. Question: Haynes refers to a 10 psi cap; I think the old cap was a 10; the NAPA is a 7 psi; our car is a BJ7. Any suggestions as to what the pressure rating should be (and there's a bunch of good threads here on original appearance caps, but I didn't find a pressure discussion).
Thanks
Doug
 
I'm thinking the 7 Lb cap is the right one; it is the one on my car.

I remember sometime in the 80s, I was experimenting with raising the boiling point of the water (I was living in southern Louisiana at the time). I might've tried a 10 psi, but I know the next jump to 12 psi was causing the uper tank to bulge! Fortunately, it didn't cause a permanent distortion, but it was enough to convince to drop the pressure back down.

In retrospect, I should've fit the coolant recovery tank then, instead of waiting until a couple of years ago (see the other thread where I just replied).
 
I'm thinking the 7 Lb cap is the right one.

Yep that is what the originals take.----Keoke
 
Thanks guys! 7 psi it is!
Also stopped in at a rad shop and chatted with the chap there, and 7 psi was his gut suggestion as well.
Doug
 
Back
Top