> >> >----------
> >> >Vehicle in question: 1967 MGB/GT
> >> >Problem: Overheating. Temp gauge reads normal when ambient temp is below
> >> >80F, but rises to 212 when sitting in traffic or travelling over 65 mph
> >> >if the ambient is 81F.
Have you checked the temperature sending unit? You mention replacing the
T-stat and water pump, but make no mention of the TSU. Even if your
guage is reading properly, it's only as good as the information it's
Does the heater work? One would assume, were the car really
overheating, you could lose a little heat by running the heater. If, on
the other hand, the heater doesn't come up to temperature quickly, then
perhaps the car's not overheating atall.
I'm not sure how practical this would be for you, but if you can get a
volumetric pressure meter (the kind we use in water lines when testing
them, with a reducer on the bore or a smaller bore) and put it inline
around your lower radiator hose connexion, perhaps that would tell you a
little more about the condition of your water jacket. Temperature and
pressure are different measures of the same gradient; a higher pressure
will result in a higher temperature, and the only way I know to increase
the pressure in a closed system like that is to restrict the flow
significantly. Then again, I'm no physicist, and perhaps one of the
other worthies on the list might have a more cogent explanation to
Finally, did you try swapping in the old water pump to see if the
problem persists? You could've gotten a bum pump right out of the box.
75 MGB 'Rags'