Outlook / Traverse / Acadia / Enclave A/C problems

[lanxer57]

The outlook shares most of its mechanical parts with the chevrolet traverse, gmc acadia, and buick enclave. This seems to include the A/C system. My mother drives a Traverse. I am already on this forum, and am too lazy to join a traverse forum. I recorded a video of testing the air conditioning system with a manifold gauge at an ambient temperature of about 90 F, and spraying the condensor with a hose. https://youtu.be/P1nV8IO4Xww
The cooling fans seem to be working at both speeds. The compressor cycles on and off every few seconds after the vehicle is started, the needles on the gauges oscillate with the compressor. It does this for a few minutes or so before shutting off entirely, this is why I manually overrode the compressor, forcing it to run constantly. Even with the compressor running constantly, The high side pressure is too low, and the low side pressure is too high. spraying the condenser with a hose seems to help this pressure difference a little bit, but not enough. I tried evacuating all of the refrigerant from the system, and then left it, and it held vacuum steadily, I also did not see any residue from leaking refrigerant with a UV light, after refilling it, it continued to act in exactly the same way. The A/C seems to work fine when the vehicle is in motion, I initially thought that it was related to airflow, but I now believe it is related to engine RPM, as revving the engine for a few seconds seems to make it work better, and correct the pressure readings. Also, The compressor sounds a bit like a diesel engine, I did not listen very closely after replacing it a few years ago, Is it supposed to sound like that? I suspect that the compressor may have failed again, Any ideas?

[fdryer]

While all vehicle ac systems operate to create cold air, there are several differences

1-Saturn Vues use scroll type compressors. Compressor types; piston, variable displacement vane, scroll.

Which compressor is used in Traverse?

2-Was this repair performed by dealer, repair shop or diy? What was the reason for replacing the compressor and was the filter/drier replaced? If diy, what amount of refrigerant was installed? Oil amount?

3-If Traverse uses a scroll compressor search past threads in Vue forums about specific problems with scroll compressors having leaking/faulty scroll control valves (Ford also uses them) otherwise ignore this alert.

As a rule, Saturn ac compressors run continuously, never cycling in normal operation. I don't know if Traverse runs compressors continuously or not. Something is triggering this system to cycle off/on repeatedly, to protect itself from; under charge/leak, over filling with more refrigerant than required, contamination if sealer was used, and any other unanticipated issues if a repair wasn't done correctly. Although 300 psi seems high, this may be from high ambient temps (90F). Low side pressures can be between 45-55 psi.

The chart is a general purpose r134a temperature/pressure chart relative to ambient temperatures. Although very good for reference, GM service manuals should be used.

[lanxer57]

The traverse A/C compressor uses pistons, I took on apart that came off of it a few years ago, I counted 6 cylinders in the back arranged in a circle. I do not know if there are any in the front, the pulley was in the way, if there are, than the total would be 12 cylinders. Dad said we replaced it twice a few years ago because the clutch was not working, this is clearly not the case now... Dad would not say where he got the A/C compressor that is on the vehicle, because he refuses to think about it until I fix the power steering, which failed yesterday.

Any Ideas? Is the compressor worn, or should I try other diagnostic procedures?

[fdryer]

Six piston GM compressors were standard from years ago. As a rule, they're as reliable or more so because they were standard on r12 systems and rugged. They became less used as different compressor designs are more efficient, smaller and use less power as vehicle engine bays became smaller with less room. Piston compressors also have other different parts; a mechanism near the hvac box (outside), a throttling valve different from thermal expansion valves used in r134a systems. And orifice tube that's basically a nylon screen filter and restriction to control refrigerant flow. Either the throttling or orifice tube controls cold air production in the evaporator coils. The orifice tube fits into one of the high pressure hoses and replaced when a compressor is replaced otherwise debris can choke refrigerant flow resulting in several problems similar to what you're experiencing.

Review your ac system and check for an orifice tube. If used, this may be clogged and causing problems. A compressor replacement usually requires replacing the filter/dryer, condenser coil, txv or orifice tube to restore factory ac function. As diyers, careful examination of oil from a system can help determine if the condenser coil can stay but at the least, drier and orifice tube are replaced.

[fdryer]

Some research shows Traverses use block style thermal expansion valves (two), suggesting front and rear evaporator coils with separate filter/dryers.

What year and engine size? When compressors were replaced, was oil, filter/drier(s) replaced and repaired system thoroughly evacuated before refilling with the appropriate amount of r134a?

[deecot]

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