The A/C stopped working in my wife's 6 cylinder 2004 Alero. No smells, visible leaks, etc - just no cool air coming out of the vents. I took it to a repair shop and they added refrigerant ($80). The A/C worked fine for about 2 1/2 months (but she doesn't drive the car very often), then no cool air again. Took it back to the shop, they replaced refrigerant again and added UV dye ($60). They reported no visible dye leak, said it probably indicated a bad core, but we should drive the car a couple of days, then bring it back for another look for a dye leak. We brought the car back 4 days later, again no visible dye leak. We were told this means a bad core, necessitating a $990 core replacement.

Before going ahead with this repair, I want to be sure that the diagnosis is correct. Does the absence of a dye leak truly pin down the problem to the core? Is there a more definitive test (sniffer?) that should be run before making this expensive repair? Is $990 a fair price for a core replacement?

Finding some leaks can really take a lot of talent. The evap core is not easily accessible but does leak very often. He's using process of elimination and that's a bit risky. I usually drill a hole ring in the case so i can get a sniffer right near the core to confirm the leak. You can also look for traces of dye with a U/V light on the inside of the condensation drain hose.




78 Corvette Pace Car For Sale-18k mi orig-Florida

It's a pill sometimes but dye would be found in "condensate" (the water they make when working) or in the drain tube. I would never spend the effort never mind $$ without a real diagnosis!

T
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Tom Greenleaf - MetroWest, Boston

I have to agree with Tom & HT, that is a huge gamble just because they can't find any dye. If the system is low on oil then the dye isn't going to work too well and can easily dissipate with out sticking to anything...... I've seen more compressor seal leaks than cores on that type system. As HT suggested, they should confirm the leak with a leak detector (sniffer) The newer ones with a heated diode work very well with almost no false positives....

This job calls for 8 hrs so 1k is about right for the job.