Here's a problem that I have not seen discussed on the list that I'd like to
have some help on. I have a 1961 TR3A. It runs fairly well in warm and hot
weather, but it undercools. On the warmest days of the summer, temps while on
the road will be 135 or so. If I let it sit and idle on the hottest days, it
will reach the point where the thermostat opens (160 F) and stay there. Oil
pressure is very good. Starts out around 70, and when warm, doesn't drop
below 50. Compression is right around 130 to 140 on all 4 cylinders. The
thermostat has been tested in a pan of water and does open at 160. It is the
old style skirted thermostat. The thermostat housing seems to be in
reasonably good condition. The carbs, which I am going to rebuild because of
a little leaking and throttle shaft wear, are as well adjusted as possible,
and review of the spark plugs indicates that it is not running rich or lean.
It is a stock size radiator, which was re-built with a little more efficient
core, which does not have the hole for the starter crank. The water temp
guage is reasonably accurate (or at least a modern one purchased at Trak Auto
gave the same readings.) The real problem is in the winter, when the temp
needle won't budge off of 90 F. I don't mind the lack of output from the
kneecap heater, but the car just won't idle or run nice when it's that cold.
I'm planning to screen off a portion of the radiator with cardboard, and
experiment with that. Incidentally, the exhaust system is stock. Any ideas
out there? Inquiring minds want to know!
Paul Vander Woude
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