George,
Pressurized cooling systems don't necessarily prevent overheating. The
pressure cap will increase the temp at which the coolant boils (something
like a degree or two per psi), but it doesn't sound like you're boiling anyway.
I think most Healeys call for a 7psi cap; which "Shop Manual" are you reading?
Sounds more like you have blockage in your radiator, block or both. Have
you had the radiator rodded and pressure tested? Any idea if the block was
hot-tanked at the last rebuild? Is the coolant gunky, and what ratio antifreeze
to water are you using?
Thermal conductivity of water is greater than that of antifreeze. If you're in
a warm climate you can get by with less antifreeze, or none at all if you use
a rust-preventative. With or without antifreeze, you might try adding
Water Wetter--it should buy you a couple degrees.
Failure to grease the water pump--assuming you don't have the sealed-
bearing type--will result in leaking of coolant and noise, up to the sound
of your fan hitting your radiator.
Belt-tightening is a matter of feel; the general guideline is about a half-inch
of deflection per foot of belt if you press on the belt with "moderate" pressure
from your thumb or finger. "Moderate pressure" is pretty subjective, but
I'd guess more people err on the side of overtightening than undertightening.
Grab the fan, and you should only be able to turn it with a fair amount of
torque.
BTW, the behavior of your car is "normal" if you happen to be in traffic
in Phoenix in July ;)
bs
***************************************************************
Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
***************************************************************
-------------- Original message ----------------------
From: George.Alexopoulos@beldencdt.com
> Having problems with overheating while in traffic...after a few minutes
> (literally maybe 2-3 minutes) the needle sky rockets to the max.
>
> Once I get moving, it tends to cool down but will immediately shoot up
> again if I slow down.
>
> I had the thermostat changed last winter as well as a coolant flush and
> change but the problem is still there.
>
> I noticed reading the Shop Manual that the cap for the radiator is rated at
> 10Lbs...but mine is only rated 7Lbs.
>
> Could that be the cause???? Could not having greased the water pump for a
> long time do that??? Could the tension on the belt be too loose, if so,
> what guidelines should I use to tighten it???
>
> Any help will be huge!!!
>
>
>
>
> Regards,
>
> George
> 67 BJ8
> 78 MGB
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