I'm trying to diagnose a coolant leak on a 1995 Chevy Corsica V6. Just
below where the two heater hoses enter the firewall, there is a rubber
spigot coming out of the firewall. It sticks out maybe a couple of inches,
then bends 90 degrees to point at the ground. It's open, i.e. no valve, no
cap, no hose attached. The car recently started leaking a significant
amount of coolant out of this spigot (for lack of a more descriptive word).
It's a steady trickle when the engine is warm.

What is this thing?? I can't find the answer online anywhere. I've never
heard of a heater core having an overflow drain.

Thanks,
~kevin

The "spigot" is a drain for the HVAC system. Normally you would see
rainwater that got into the system from the intake in front of the
windshield. You're not so lucky what you are seeing is evidence that
your heater core is leaking.


Kevin wrote:

Kevin,

That is a drain for the A/C evaporator. It is normal for water to drain
there when the A/C is on. Are you sure it's coolant? Have you had to add any
coolant? Feel the stuff that hits the ground. If it is slippery between your
fingers, like oil, then it's most likely coolant. Yes, it can come out of
the A/C drain tube. The heater core is mounted next to the A/C evaporator
core on that car.

According to my records, your vehicle uses dex-cool coolant (Orange or
pink in color). This can sometimes look clear when it's on the ground.

A more likely source for a coolant leak on your car would be the intake
gaskets. The 3100 V-6 has had many problems with this. Have someone pressure
test the cooling system, and look for leaks.

GMdude.

It's not rain water. It's condensation from the A/C evaporator coil.

GMdude

Kevin,

If you had a leak at the intake, it would be on the passenger side or
driver's side of the intake. That's where the coolant passages are.

GMdude

"Kevin" wrote

Sounds like you have a leaking heater core. There isn't anything
else in the HVAC housing that would leak antifreeze.

Ian