Mark:
You have an air "bubble" in your cyl head / cooling system. Try
squeezing the lower hose repeatedly when engine is at operating temp,
with the rad cap open, to dislodge it. you can also "pump" the top rad
hose too with the rad full.
Brian
Mark Purtell wrote:
>
> Thanks for the help already, but I'm still a bit puzzled by the MGB's
> cooling system. I flushed the system, and refilled the block and radiator
> with coolant. Then I drove the car (to open up the thermostat) and added
> more coolant (I did this twice). Now when I drive the car, the
> temperature needle moves up to the middle of the gauge temperature at a
> "normal" rate, and then once it reaches about halfway, it stays there for
> a minute or two and then it shoots up to the overheat area-it doesn't
> always reach "overheat", but it gets close and will occasionaly peg the
> end of the gauge. Once the needle says "overheat", as I drive faster, the
> temperature gauge moves down from overheat, but never remains in the
> middle of the gauge. The engine doesn't seem really hot, and my Hayden
> fan is running fine. I have already replaced the temp sensor and have 180
> degree thermostat in it.
>
> Thanks in advance-
> Mark
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