for past 3 years have had to replace freon in 98 Lumina AC system. First effort to use dye to find leak failed. Now mech says it's a compressor leak. How does he know that. Wouldn't the dye have shown the leak?

Speaking of dye - if there is a very slow leak, wouldn't it make sense to charge the system, including the dye, and then come back after a few weeks to look for the dye trace, giving it time to build up? or is the dye only visible when damp.

car has less than 30,000 miles.

Thanks for your help.

pete

 

The leak could be in the evaporator. If it is, the water from condesation will wash it away and you'd never see it.

It is possible that theres a leak around the compressor. In most cases of leakage, its escaping around the service valves. I'd replace the lines and compressor and then see what the problem is.

 

How well do you know your mech? Is he willing to fix it free if he replaces the compressor and that's not the problem?

This "Phantom Leak" is a problem which usually occurs in older cars.

Maintenance note: In order to keep your A/C system healthy, it's wise to run it once a week for a few minutes in the wintertime, to circulate fluids in the system.

 

Yeah. He's right, the purpose is to circulate the refrigerant oil.

R134a, best I remember, is not picked up by a halide leak detector, so if you were really serious about finding the leak, you could do a pump it down and fill a 95% nitrogen 5% R22 mix in the system and search for it with a halide leak detector.

 

Any current mechanic worth his salt would have or have access to an electronic leak detector that would easily pick up R134A. In fact these leak detectors have been around since the introduction of 134A.