Chris,
Without knowing more history and indepth symptoms of your overheating TR4
it's hard to determine correct diagnosis but ..
Yes you can just let out a little coolant from the bottom at the radiator tap
- since thermo housing is highest point a few cups let out at bottom would do.
While you have thermostat out look at your 'bypass port' (little square hole)
inside the aluminum base housing - this controls capacity of 'recirculation
flow' for warm-up but hole can get eroded to double normal size. As designed
a 'sleaved' thermostat blocks this port hole when motor gets warmed up (then
directs all coolant to radiator). But typical aftermarket thermostats don't
have the sleeve so your 'bypass recirculation' continues even when thermostat
opens (and you never get proper full radiator use). The port should be about
6x12mm square hole. If it's eroded to a much larger size than that, your
coolant will be getting even more diverted to just recirculating through
engine without going through radiator. An 'Olde tyme' proven fix is to insert
a standard 1/4" holed washer in your 'bypass hose' to restrict 'bypass
recirculation' flow fulltime (versus changing flow capacity between hot and
cold running) - that's probably the least you should do unless you're
fanatical (like me) for the original setup. Installing the aftermarket $36
'sleaved' thermostat (see Moss) would help direct your coolant flow to the
radiator at running temps (if port hole is in decent shape).
As far as tightening your fan belt (for water pump pulley)- THE TR4 IS VERY
SENSITIVE TO AN OVERTIGHTENED BELT (ruined bearings, premature belt failure,
etc). As long as you maintain factory spec of 1/2"-3/4" of slack (finger push
on longest length of belt) you should be OK. If you cannot manually turn the
water pump pulley by hand (make it slip) the belt should be considered plenty
tight.
ps; if the front of your radiator is missing the factory air funnel cardboard
shroud - get it - it's very functional for cooling!
Carl
'63 TR4 since '74
>>Do I have to drain my radiator to remove the thermostat? I have been
running
hot/overheating and I want to test the thermostat. The radiator
fluid/antifreeze, looks and tests good, so I'd like to leave it in if
possible.
Chris
1967 TR4A<<
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