[TR] wrong cap

[Greg Lemon]

I don't know the rating of a TR3B cap, but what you describe is a common 
occurrence, you top up the radiator, run the car, shut off the car, heat 
from the motor heats up the coolant, which is no longer circulating, to its 
highest temperature yet, it expands and leaks out the cap, two solutions, 
install a catch/return tank as they started to do in the sixties, you can 
get one from a later LBC, or a generic plastic one from a local chain auto 
parts store.  I used a generic one on a car I used to have, and was 
surprised when it not only caught the overflow, but returned most of it when 
the motor cooled back down.

Plan B, let it overflow a couple times and it will reach its sustainable 
level.

Greg Lemon