coolant leakage (*%#*!!)

[Kerry Griffith]

Gents,

When my car gets hot enough, coolant leaks from beneath the expansion 
tank cap. My techs (I'm beginning to suspect a strong primate 
connection) installed a new cap.
The question: If the oil and coolant guages are within normal 
boundaries, and no idiot lights are lit, does the abovementioned puking 
indicate the expansion tank-cap interface, or is the cap designed to 
bleed off coolant if a problem exists elsewhere?

Best regards,
Kerry

P. S. Despite the fact that the car uses no oil (perphaps from a 
life-long diet of Mobil 1 - but that's another thread we probably don't 
want to revive) my supply of emotional straws is getting low. I've 
treated the car to the best maintenance,  parts replacement and care 
possible (including annual flushing of coolant) during its 11ish years 
with me, the end may be nigh- unless you gentlemen come to the rescue 
by telling me the coolant issue is easy and inexpensive.