After taking my 2004 C5 to three different AC shops (and one was the local Chevy dealer), my AC continued to refuse to come on or blow cold while sitting parked or driving slow. It has finally been fixed by Chevy (the former mechanic that couldn't fix it but still replaced parts! was fired from Chevy dealer), and the cause was a surprise to me.

Symptoms:

1. Car would only blow cold after getting moving down the highway, then normal.
2. Attempting to engage the AC (especially when hot outside and car warmed up) would result in either the climate control AC light flashing and then going off, or refusing to come on altogether.
3. AC gauges indicated correct amount of freon.
4. Purged and refilled freon twice (no change).

The fix:

Replaced the radiator coolant thermostat!!

No wonder the 'AC shops' said that they could find nothing wrong with the AC system, and they were right. There wasn't anything wrong with it!

The car's temp gauge would show it climb to a little over 220 while idling, but nothing in the 'red' area, to confound everyone. It took me close to a grand and 2+ years to fix this!! I was about ready to dump the car when my Chevy dealer told me they had a new young hotshot mechanic. Did they ever! Took him all of 30 minutes to diagnose it!

 

So, the thermostat was reading the temps correctly but was bad? I'm confused because 220 at idle is normal?
Good to hear you got it solved though

 

Well I am confused too...kudos to the mechanic for sure figuring this one out.

 

Something is missing in the story for sure.

A few * on the radiator is not going to make much difference on the condenser and cooling because the air goes through it first. So they either fixed it on accident or don't want to tell you because it was something they should have found before.

 

Voting the latter

 

It works now and that's what counts but I'm with the others - something just seems strange.

 

The only thing I can think of is (its this way on my Eagle Talon TsiAWD) is when the radiator fluid tempertures get too high, the AC automactically cuts off. But what confuses me is the OP said temps were only reading about 220 which is NOT too high for the C5.

 

220 Is pretty much the normal operating temp. I been in stop and go traffic at 100 deg with the coolant temp at 235 and still had AC.

 

has the car been tuned, maybe the tuner changed the setting?


i agree something just is adding up here.

 

Doesn't make sense to me either. But then, I'm old and don't know much.

 

What the hell does changing the thermostat have to do with the AC with temps only in the 220range Even if outside that range, I'm not aware of a connection there......

 

Its amazing what a can of Freon will do.