bigdog225

Ok 1996 Cobra. A/c went out and took it to the shop on Friday. They said they couldnt find a leak so charged it up and said bring it back when it leaks out. Said they put some dye in it. saturday morning A/c was out again and of course they were closed.

Found a buddy that could pull a vaccum on it. Held strong no sign of leak. Said to try a can of super seal. We did and charged the sys back up. Hel a charge for 4 days this time.

Took it back to the shop they said they couldnt find any dye anywhere. So I left it with them to search deeper. I get a call a bit later and am told its leaking from the compressor and the evaporator and its gonna cost between $1300 and $1600 to fix.

For a leak they could find twice thats now all the sudden 2 leaks sounds fishy to me. I guess the compressor could be the culprit seeing that the system held a vaccum but I know it has turning parts etc when in use, but how is he assuming the evaporator if he cant even get to it without pulling the dash out??

Gladly hear all thoughts on this one...

cliffyk

Vacuum is of course negative pressure, and at the very most only -14.7psi.

However the AC system operates pressurised, at 40-60psi on the low side of the expansion valve, and as much as 350+psi on the high side. When not operating the pressures will tend equalise at around 90psi.

So, between the opposite and greater pressure it's quite possible for the system to hold a vacuum but leak under pressure.

The evaporator is not immediately visible, so it could leak with no dye showing until it had leaked enough to show up in the condensate drainage--the compressor can be bad without leaking, there are as number of other things about it that can go wrong.

Bring the car somewhere else and get another quote, I think you'll find that it's going to be pricey as the dash has to be removed to replace the evaporator coil.