Coolant leak over pass side cat

[Jkhoyt]

2001 LS V8. Working on a friend of mine's LS. Car ran hot one time, went into low power mode? pulled over, let it cool down, ran fine afterwards. Coolant needed to be added at the front of the motor, Degas? bottle by the windshield was normal level.

During the bleeding process, I noticed some coolant leaking. Nothing in the engine bay that I can find, from the bottle, the front of the motor, or the lines as they go back to the firewall. Coolant is leaking from just above the passenger side cat, right where the 02 sensor is, but only when the heater or AC is on.

Am I most likely looking at the heater core then? How hard is it to work on on these cars? I tried the search, but didn't come up with much for the heater core. Thanks in advance!

 

[joegr]

Are you certain that it was coolant and not just condensate from the AC?

Condensate (clear water) is normal when the AC is on and comes from a drain in that area.

AFAIK, heater core leaks on the LS are quite rare, but possible.

Degas bottle leaks are very common.

 

[Jkhoyt]

It's a very steady drip, probably 2-3 drops per second, but only when either the AC or heater is turned on. It starts as soon as it's turned on, and stops moments afterwards.

 

[joegr]

It's a very steady drip, probably 2-3 drops per second, but only when either the AC or heater is turned on. It starts as soon as it's turned on, and stops moments afterwards.

That's the rate the AC condensate drain would flow. Assuming that you have the correct anti-freeze mix in the coolant, it shouldn't be hard at all to tell if it's clear water or green coolant.

 

[Fla02LS]

It's a very steady drip, probably 2-3 drops per second, but only when either the AC or heater is turned on. It starts as soon as it's turned on, and stops moments afterwards.

Seriously, you just answered your own question right there. Its the a/c. I've sat in a parking lot for a good while with the a/c cranked and actually had someone come over and tell me my car had a leak. After about 20 min there was a pretty sizable puddle, especially this time of year when its really humid outside. Anyways, no worries, a/c.

 

[Jkhoyt]

Well, then, I feel like a doofus. My only point of comparison is my older cars, which would take awhile before dripping from condensation. Thanks. Since I bled it, temperature has been fine. Hopefully it just had an air bubble in it.