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Strange Cooling Issues [Help]

EliteZ on Mon September 22, 2008 10:30 AM User is offline

Year: 1998
Make: Pontiac
Model: Trans Am
Engine Size: 346
Refrigerant Type: R-134A
Ambient Temp: 90

Hi guys.

First purchased car, A/C worked. Never used A/C. Tried using it 8 months later, was blowing warm. Charged it worked fine for 3 months. Charged it again, 3 months. Brought to an A/C tech friend who used his manifold and large can to diagnose and everything. He noticed that there was a lot of gas in the line but not liquid. He let out excess gas and refilled w/ liquid. It blew cold again, temp out of vent was around 56. Lasted about a month and a half (In all cases this is a gradual decrease in performance til it is unable to adequately cool).

Unhooked system. Replaced Orifice Valve and Drier. Made sure that Evap and Condenser were not blocked. Excess oil was removed from Evap. Hooked everything back together. Pulled into vacuum for about an hour and filled freon to stock specs.

Blew cold. Now about 2 months later I am still having the same problem of it gradually getting warmer. I have no leaks. Compressor still runs. Still blows coolish(~77) out of the vents lower then ambient. No longer efficient to cool whole car.

iceman2555 on Mon September 22, 2008 10:48 AM User is offlineView users profile

It has a leak! If this is not indicated with the use of a leak detector....add some dye to the system and recheck. This vehicle should have the GM V7 compressor. Install the dye...recharge and operate the system for several days....then using the correct equipment...check the compressor for a possible shaft seal leak. This is not an uncommon problem...esp when a vehicle has been operated with a possible undercharged system.
Also check the case for possible leak areas. The compressor 'gut' pack seam is a common area for leakage as well as the discharge sealing washer.
All in all, what is being described is a classic case of an undetected leak.
Good luck!!!

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

mk378 on Mon September 22, 2008 10:54 AM User is offline

Yes it seems that no one ever found and fixed the leak which it obviously has. If there really were no leak, one charge of refrigerant will last the life of the car. It is not consumed during operation, the only reason that more needs to be added is because it has leaked out.

Also some leaks lose oil, if you keep recharging such a system you risk running out of oil and destroying the compressor.

Do not be tempted to use stop-leak! It doesn't work anyway.

tony1963 on Mon September 22, 2008 11:39 AM User is offline

On these models, I have found stress cracks on the line sets that run to the compressor. The leaks are typically along those lines and you can see a telltale oil trail.

When leak testing, be sure that the fan is off and the car is off, too. Any air circulation makes detecting leaks with a detector difficult.

Grove Automotive Group, Inc.

An Alabama Corporation

EliteZ on Wed October 08, 2008 7:08 PM User is offline

I see thanks. I had to recharge it and it blows cold again. I put a can of stop leak-refrigerant-dye in it and an additional can of refrigerant. I don't see any oil or dirt trails on the top side, or down near the compressor(nothing that would indicate compressor leakage vs. oil/grime buildup).

Assuming that can actually does/did contain some kind of dying agent, What do you use to look for leaks with it? Would the cracking/fragility of the rubber lines be evident?

If its the seal in the compressor, how do you go about replacing it? Its like a 6 dollar part, and a 250-350+ compressor.

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