[TR] Overheating issue

[Randall]

> In other words, it goes like a "bat out of hell".

So did my Dad's TR3A (first one I had to maintain, over 40 years ago).  It
would run right up to red line in 4th gear with no problem at all.  But it
still had a severe overheating problem.  I believe (in retrospect) that the
primary root cause with it was either worn fuel jets, or some ill-considered
carb mods by a previous owner.

> From what I've heard from
> others, the cap should not come loose at 210 degrees, thus depressurizing
> the system,

Yeah, I said that too.  Cap should not come loose by itself, even with the
system actively boiling.

> So maybe that's the area of questions.  With everything being equal,
> engine timed and tuned, do you think in extreme heat and driving pretty
> hard uphill, that 210 degrees is acceptable temperature? 

Well, maybe.  Depends on things like how accurate your temp gauge is, and
what kind of thermostat you are running.  With no thermostat at all and an
accurate gauge, I would say that definitely indicates a problem.  I can go
up Grapevine hill with my foot on the floor (as long as no cops around) in
100F heat, and the electric fan won't even come on.

> When getting to
> that temperature range, or higher, would you expect the radiator cap to
> get loose, or blow off via the overflow hose?

Cap should _never_ come loose on its own.  It might play a tune for you, but
it should stay in place.

Depending on circumstances, you might lose coolant through the overflow; but
in general not at 210F unless the system was overfilled or you are at high
altitude (like 5000 feet or more).  IIRC, 33% glycol, and a 4 psi cap,
should boil around 215F at 7500 ft.

-- Randall