[Healeys] BJ8 radiator cap issue

Bob Spidell bspidell at comcast.net
Fri Mar 29 08:09:04 MDT 2013


Doesn't make sense, at least according to the laws of physics I pretend to understand.

If you didn't boil or lose coolant with a 7lb cap, it means you never reached 7lb. pressure in your cooling system.  So 
the 10lb cap should never open, either.  The additional 3lbs pressure would only give a few more degrees before boiling, 
which doesn't appear to be an issue with your car (Law of Physics: the boiling point of a fluid is directly related to 
ambient pressure; that's why boiling cooks foods slower at higher altitude).

IOW, the cap doesn't regulate pressure in the cooling system (like a voltage regulator)--it's there to keep your hoses, 
etc. from exploding if your engine overheats.


Bob


On 3/29/2013 6:42 AM, Dan Stromquist wrote:
> Water pump issue?
>
>
>
> Hi all, about 2 months ago there was a thread indicated that the correct
> radiator cap for a BJ8 was a long neck 10 lb. cap.
>
> News to me but since a couple agreed, I ordered one to see if there would be
> a difference.
>
> I have been running a 7 lb. cap with 180 degree sleeved thermostat. With
> this setup, I've had an idle temp right at 180 degrees when warmed up.
>
> When I changed to the 10 lb. cap (with same thermostat) the BJ8 immediately
> ran 200 - 205 degrees at warm idle. Switching back to the 7 lb. cap brought
> the idle temp right back down to 180 degrees.
>
> Why would this be?
>
> Randy
>

-- 
*******************************************************************
Bob Spidell           San Jose, CA            bspidell at comcast.net

*******************************************************************


More information about the Healeys mailing list