[TR] Overheating issue

[Randall]

> If 220 is enough to cause a boil over, I'd think the capture bottle would

> fill up but not unscrew the cap. Then when it cools down it would suck the

> fluid back into the radiator. I think it's the radiator cap and plan to

> replace it.

 

The cap should definitely not unscrew itself; even when boiling over.
However, the fault may be the radiator neck rather than the cap.  There are
two little tabs that the cap is supposed to catch on; the tabs may be worn
down or torn up (or even deliberately removed).

 

Any radiator shop should be able to replace the neck for you for not much
money, but you'll probably have to remove the radiator and they may have to
order the neck.

 

Another possibility is that you have the wrong cap.  The original TR3
radiator takes a special cap that has a longer "reach" between the sealing
surface inside the neck, and the top of the neck.  IIRC that distance is 1"
on a TR3, 3/4" on the vast majority of cars (including later TR4A).  If you
have installed a short reach cap by mistake, there might not be enough force
to keep it latched in place.

 

It's best to double-check that distance; as some crazy people (including
myself) have had the neck modified to accept a modern short reach cap.

 

My experience has been that the supplied original type caps (with the long
reach and 4 psi pressure limit) will not work correctly with a recovery
bottle; even if you add a seal between the cap and the outer rim of the
radiator neck.  Apparently, they leak air through the center rivet (but I
couldn't make one work even after surrounding the rivet with RTV).  What
worked for me was to convert to a modern cap designed to be used with a
recovery bottle.

 

FWIW, I didn't want to clutter up the engine compartment, so I hid the
bottle next to the radiator under the RH horn.  I like it there, but of
course I fill through the radiator neck, not through the bottle cap as it's
almost impossible to reach.

http://s258.photobucket.com/user/TR3driver/media/TS13571L/DSCF0013-2.jpg.htm
l

 

-- Randall

 

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