A/C Compressor heading south

[Al 96 Ram Air T/A]

Im gonna go out on a limb here, being new here and all, and I certainly hope this doesnt come off the wrong way. But Im not sure I understand your reasoning for wanting to change out your compressor, Al. A refrigerant leak wont leave anything more than a damp area immediately at the spot its leaking, and even if it was leaking enough to leave an oily residue, it would just about hafta leak enough that it would no longer be cooling. As far as changing it so that you wont hafta change other components in the event of a failure, well, if you change the compressor and accumulator, thats pretty much the major components that would need changing if it DID fail.
I would suggest finding out if its actually leaking, and where, before I just started changing out parts. It could be that you do have a leak around the compressor, but it may not be from the compressor. And if its still cooling, then it evidently hasnt leaked much. Hope this helps, Al. And I hope my opinion doesnt seem disrespectful to anyone

P.S. Does this count as my official introduction? lol

No offense taken...all good questions. In the a/c sytem, the oil is designed to lubricate the compressor. As the PAG leaks out, the compressor will eventaully fail. When it does, it frequently send parts through the system which can and usually does clog the condensor and evaporater. Wanting to change out the compressor prior to this is why I want to do it sooner than later. In all honesty, I'm not sure how long the oil has been leaking. The compressor may be running dry as we speak. As such, it's cheap insurance to do it now (or in the spring like I plan) rather than at the peak of summer when it fails.

[fastTa]

No offense taken...all good questions. In the a/c sytem, the oil is designed to lubricate the compressor. As the PAG leaks out, the compressor will eventaully fail. When it does, it frequently send parts through the system which can and usually does clog the condensor and evaporater. Wanting to change out the compressor prior to this is why I want to do it sooner than later. In all honesty, I'm not sure how long the oil has been leaking. The compressor may be running dry as we speak. As such, it's cheap insurance to do it now (or in the spring like I plan) rather than at the peak of summer when it fails.

Do you know anybody with a set of A/C manifold gauges that you could borrow so that you can look at the high and low side pressures?

[Al 96 Ram Air T/A]

As a matter of fact, yes. My neighbor is a GM mechanic...Pontiacs are his speciality.

Can't afford to do anything with the a/c now though. Just spent a small fortune doing the suspension. Will wait till the spring since the car doesn't come out to play all winter.

[CDJr]

No offense taken...all good questions.

WHEW! Im glad you took it the right way, Al. I just didnt quite understand why you were going that route at first, and I just didnt wanna see ya waste money and effort on something unnecessarily. But I see what youre saying now and it makes more sense to me.

[fastTa]

As a matter of fact, yes. My neighbor is a GM mechanic...Pontiacs are his speciality.

Can't afford to do anything with the a/c now though. Just spent a small fortune doing the suspension. Will wait till the spring since the car doesn't come out to play all winter.

I was just gonna say....it would give you an idea of how much refrigerant was still in the system, and what the head pressure and low side pressures were.

The static low side pressure should be within 5 PSI of the ambient air temp in °F. With the clutch engaged, the low side should be around 35-45 PSI. The high side pressure should be between 190-230 PSI with the clutch engaged.

[Jeff_in_Atl]

The high pressure should run from about 190 where the low pressure switch turns on the compressor to about 420 when the high pressure switch shuts off the compressor.

BTW you can read the high side pressure with a scanner hooked to the OBDII port.

If it never reaches the point where the high pressure switch shuts off the compressor at ~420 then there isn't enough freon or the compressor is shot.

[fastTa]

On a OBD-II 96, there are many things that control the a/c clutch and the high speed setting on the fans. The HSLP switch (high side low pressure), CCPS switch (clutch cycling pressure switch), HPCO switch (high pressure cut-off), and the LP switch are all involved in controlling when the high speed for the fans is activated and when the a/c clutch is said to be cut-in or cut-out.

On a 96, the cut-in low side pressure range is listed as 22-32 PSI. The cut-out low side pressure range is listed as 2-9 PSI. The 3 sensor HPCO switches also have the ability to measure refrigerant temperature at the head. Anything over 248°F cuts-out the A/C clutch.

The HPCO and HSLP switches (high side switches) have nothing to do with the cycling of the A/C clutch. The CCPS switch controls the cycling.

The "norm" for the high side while the clutch is engaged on a properly functioning A/C system is 190-230 PSI. Anything over 239 PSI is abnormally high. At 240 PSI the high speed function is activated for the cooling fans in an attempt to bring the head pressure back down to normal.

The HPCO switch will allow the head pressure to get to exactly 410 PSI before disengaging the A/C clutch, but anything over 239 is excessive and is an indicator of a problem.

The HP release valve will usually blow at around 420-430 PSI......and it is deafening loud!

[fastTa]

BTW Al, here are some of the codes related to the A/C system:

P1461 A/C pressure sensor circuit voltage low

P1462 A/C pressure sensor circuit voltage high

P1463 A/C Pressure Sensor Insufficient Pressure Change

P1464 A/C Demand Out of Self Test Range

P1465 A/C Relay Circuit Malfunction

P1466 A/C Refrigerant Temperature Sensor/Circuit Malfunction

P1467 A/C Compressor Temperature Sensor Malfunction

P1468 SSPOD Open Circuit or Closed Circuit Fault

P1469 Low A/C Cycling Period

P1470 A/C Cycling Period Too Short

Just remember that most of the HVAC codes will not turn on the SES light.