On the way to/from Triumphest my TR4A ran hot. By hot, I mean somewhere between
2/3 and full. This was especially true as the revs went up during highway
speeds of 65 to 75. As I slowed going through small towns the temp went down.
The outside temp didn't have big effect although the temp was lower when it was
40 outside. Also, opening/closing the heater didn't seem to have much affect.
Over time water escaped out through the radiator cap into the overflow
reservoir. But, even with a full radiator the car still ran hot. Of strange
note is that water was never "sucked" back into the radiator, so the reservoir
always remained full and overflowed. A couple of the guys at TrFest suggested
that my 7 LB cap was the problem. I'm hesitant in using a "shotgun" approach to
fix the problem, but even after changing it to a 4 LB cap I still have the
problem.
Today I pulled the thermostat (it's a 160 deg), and tested it on the stove. It
fully opens and closes, but it appears to "shudder" or step as it opens. It
also looks like the bi-metallic piston is off center so I'm off to the parts
store to get a $5.00 cheapy - this time a 185 deg. If the thermostat change
doesn't cure the overheating the cause is either the radiator or a blockage in
the block/head.
So, a couple of questions:
1. I'm considering using water wetter and Prestone coolant. Does water wetter
really work?
2. Is there a "flush" for the block, or is this the same as the radiator stuff?
Any suggestions as to which brand?
3. Can I test for block/head blockage? How?
4. The fact that the radiator doesn't suck back water from reservoir means that
air is getting back into the system (from somewhere). When should the "sucking"
occur, during cool down or lower revs (meaning less pressure?)?
5. Is there something else I need to look for?
Thanks!
John
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