[TR] cooling tr-3............questions on randalls post.

[Randall]

Hi Gary,

You probably meant to send this to the list, not just to me. 

> Refilled radiator and ran car with cap off in 
> order to observe and noted no air bubbles so I don't think 
> its head gasket.

Not to belabor the point, but several times now I have had head gasket leaks
that only showed up under heavy engine load (when cylinder pressures are
highest).  With Stag #1, I could literally drive around all day if I was
gentle with the throttle; but if I floored it up a freeway ramp, it would
blow all the coolant out by the time I got to the freeway.  So not seeing
bubbles with the engine just idling doesn't necessarily mean you don't have
a leak.

>  I also noted with new cap installed and 
> during revving engine there was some seapage under the cap 
> out the overflow when engine revved, this was during a 
> radiator temperature of around 185 to 188 so it wasn't boiling.

Another sign that you are getting combustion gases into the coolant.

If you don't want to have a shop do the test; there is an "old timers" test
you can try: Remove the fan belt and thermostat housing, then fill the
system so it is level full with the outlet in the head.  Start the engine,
and quickly rev it hard, 2 or 3 times; then shut it off again.  If the water
gushes out of the head while revving the engine, you've got a combustion
leak.

> I've 
> also noticed that my new cap has no rubber gasket under it.  
> There is only a steel "washer like" surface there.

That would make it an accurate reproduction of the original cap.

> I'm wondering what modification 
> Randall made to his cap for the "longer neck" tr-3 

I started with a Stant "Lev-R-Vent" cap, and tapped out the pin that holds
the lever so the cap came apart.  Then I made an extension for the center
pin, and spacers for the spring and seal.  I wasn't really recommending that
anyone do the same; just trying to make the point that the original TR3
filler neck & cap are setup with approx 1" from the top of the neck to the
surface inside where the cap seals; while that same dimension on most newer
cars is only 3/4".

But I think you've got more going on than just the cap not sealing to the
neck.  Perhaps you should disconnect the recover bottle and get the system
working without it first, so you can tell the difference.

Randall