[TR] tr3 cooling

[Randall]

> TS75434L has a 
> tendency to run just a little hot, even up in the cool 
> mountains of northern new mexico.

There are many different reasons for these engines to run hot, so whether a
particular change will help or not depends a great deal on what the problem
is.  The problem with TS39781LO turned out to be that the radiator tubes
were not in good thermal contact with the fins, so it was simply unable to
transfer much heat from the water to the air.

If you mean it runs hot at speed, then IMO changes to the fan are not going
to help.  My experience has always been that the fan does little or nothing
at highway speeds.  My TR3A had a big electric fan (you could literally see
the temp gauge move when the fan came on at idle); but when I had similar
problems with the temperature creeping up at speed, running the fan made no
detectable difference.

Same story on the Stag (although it's temporary electric fan didn't cool as
well at idle).

> Well, there might be an option 3: rebuild the water pump with 
> a high flow impeller. Is this worth it?

I didn't try that, but I've heard mixed reports from others.  My belief is
that it would be of marginal benefit at ordinary highway speeds.  But others
have said it helped with their problem.

> I'm not running any additives in the coolant (aside from 
> anitfreeze). Is water wetter or any other additive worth it 
> to help the system cool a little better?

I could not tell that Water Wetter made any difference whatsoever.  But it's
cheap enough to be worth a try; and I've heard at least one story where it
helped.

Just for completeness, you missed switching to a sleeved thermostat, or
blocking the thermostat bypass.  Again, those made no detectable difference
for me, but others have said it worked for them.  (If you do block the
bypass, I strongly suggest that you also drill a hole in your thermostat, so
some water still flows when the thermostat is cold.  Otherwise the thermal
shock when the thermostat opens can lead to a cracked head.)

After months of experimentation and frustration with my TR3A; my suggestion
is to bite the bullet and have the radiator recored or replaced.  In my
case, the difference was like night and day.  Before the change, I could not
drive 70 mph for over 15 miles in even 70F weather.  Afterwards it stayed
cool even at 90+ mph in 115F.

Randall