Alright, I've been here, done this twice. Your compressor is probably just fine if it hasn't been making any rattling or squealing noises. It is possible to develop a leak in the system somewhere, but the O-ring seals dry up and start to leak over time also.

The system only takes about 1.5 pounds of R134a, which isn't much at all. The amount of refrigerant is crucial, as is the amount of oil in the system (PAG oil, do NOT put ester oil in!)

I recommend that you do this:
1) Get a set of o-rings and a new receiver / dryer, some brake cleaner and HFCF-141B flushing agent. You will also need a gauge set and a good vacuum pump, which you might be able to rent.
2) Remove all the hoses, one at a time, and note where they go.
3) Remove the condensor and dryer. Pitch the dryer in the trash.
4) Flush the lines and condensor with a good A/C flushing agent. (I use brake cleaner followed by HFCF-141B, then blow it out with compressed air.)
5) Install the new receiver / dryer with new o-rings. But before you do, make sure you fill with the proper amount of PAG oil, as listed in the manual. Make sure that the new dryer had the shipping plugs installed, or else it is ruined and shouldn't be installed.
6) As you install the lines and condensor, (with new o-rings), they get PAG oil too.
7) Check belt tension on the compressor
8) Hook up a gauge set on the high side and low side ports, and use a vacuum pump to draw a vacuum. Check to see that the system is holding a vacuum. If it is, then keep drawing a deep vacuum for about an hour to boil out any water in the system.
9) Use a R-134A refrigerant that has nothing else in it, except for a UV dye. (no seal conditioner, leak stop, ester oil, none of that crap)
10) The initial fill is crucial. With my fill, it was 2 ounces shy of two full cans. 2 ounces is just about enough to slosh around in the nearly empty can. If you go off the gauges, the high pressure gauge may take a bit to settle out and you find that you've added too much. No problem.
11) If you find you've added too much, then do this: Shut it off, close the valves and let the pressure equalize. Put the can in an ice bath for a bit to cool it off. Once the high pressure side has dropped to a safe level, open the valve back to the can and squirt a bit of refrigerant back into the can. (That is why the ice bath, cool the can and the pressure in it drops)

Finally, if after all of this the system should work, as long as the compressor is functioning and the fan clutch engages (which you said it does). If it works for a while, then starts to blow warm air again, then great, you have a leak. This is why you put in the UV dye type refrigerant. Get yourself a black light and start looking for the source. I haven't heard of any leaks in the evaporator on these, but it could happen. For that, look for the dye coming out where the water drain is.

Hey, I have recharged my nine-five Troop twice and the 99 once with the el cheapo Walmart R134 kit and guage combo for $20. All you do is check the PSI on the L/P side...

L/P side has the large Disconnect with a blue cap. H/P is red, i.e. "stop dont touch", Not the the adapter would fit anyways

...and if it is low, add some of the R134, it comes with the oils that you need already mixed in the can. Easy. Ice Cold A/C <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />
Total Time: 3 mins
Total Cost: $20
Total saved over having a shop recharge 3 times: $517

The recharge lasted for three years in the nine-five. The 99 is still going strong after 2 summers. Even if it does have a small leak, who cares at that rate.

My .02, try the cheap route as long as you can hear the A/C clutch cycle when you turn it on.

Nice and Chilly, almost frostbite
Adam
<img src="/forums/images/graemlins/patriot.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/patriot.gif" alt="" />

Strider93 & All We'll Drive: I wanted to revisit this and thank you - not because I solved the problem, but because I WILL be starting this project now that the weather is warming and my wife is prodding! I know, I shouldn't have waited - I'm sure I'll be talking with you again.

Checked the pressure on the LOW side but it was WAY HIGH, so I decided not to charge it for fear I might screw something up. Pressure read close to 90 PSI and ambient temp here is only about 60 or so in our garage.

Could charging help you think?

IF THAT PRESSURE READING IS WITH THE ENG SHUT OFF , IT IS PROBABLY OK, AS THE HI AND LOW SIDE WILL EQUALIZE WHEN THE COMP IS NOT WORKING , CHECK THE LOW SIDE WITH THE ENG IDOLING, IT SHOULD BE IN THE RANGE OF 30-40 PSI , LOWER MAY MEAN CHARGING IF IT GOES WAY LOW OR INTO A VACC ON THE LOW SIDE AT IDOL, IT MAY JUST NEED CHARGING ,,BUT BE CAREFUL IT IS VERY EASY TO OVERCHARGE A 134 SYSTEM AND PRESSURES CAN GO VERY HI VERY QUICKLY.. AND BE CERTAIN YOU ARE WEARING GOGGLES , JUST IN CASE THAT STUFF IS A NASTY CHEMICAL.. JERRY

Actually that pressure WAS WITH the engine idling - any comment on this?

I think I'll get a good set of gauges and follow the procedure given here and in the shop manual, and will keep you posted. Thanks.

OK YOU ARE GOING TO NEED A GOOD SET OF GAGES , THAT PRESSURE IS WAY TO HI FOR THE SUCTION SIDE OF THE SYSTEM, IF IT IS TRULY THAT HI AND THE COMP IS WORKING CORRECTLY THE HI SID E IS GOING TO BE WAY UP THERE ,LOW SIDE SHOULD NOT BE OVER AT THE VERY MOST 50 PSI ON A HOT DAY, OVER CHARGE , BLOCKAGE OR A BAD COMP, SEE WHAT THE HI SIDE READINGS ARE, JERRY

Jerry;

Thanks for taking the time - yes, I will go find a good set of gauges and try to diagnose this. Going on work travel for a week so it will liklely be next when I get to this - do have any suggestions other than the procedures listed here? Have you done this before?