AC Expert Opinion Please… Does the AC compressor need to be replaced?

HotZ28

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The control valve can be replaced, but may require removing the compressor.
 
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2011 Lacrosse CXL AWD
That's good news. How do you tell if that's the problem? Just replace it or is there a way to check it?
 

Globetrot1

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LaCrosse CX, (2008, first gen) 3800 V6 Series III; previous: Regal coupe (1992) 3800 V6 Series I
Nothing else was performed. The Tech seems to be very knowledgeable therefore, I did not dare to question him...

I suggest sidestepping this attitude. But then I don't know if this is someone who has been your mechanic/tech for a long time and has been straightforward with you or a lauded tech at a dealership where you have your car serviced every now and then. I had a big problem several years ago with a dealership where I had my car serviced for years. Old school LaCrosses don't run into many issues in their initial years and, here, right after the extended warranty expired, the service writer was on it with a proposed expensive fix that might be coming up. I kept an eye on the area (performance, noise, leaks) and took it to two other dealership for the next 2 oil changes. There was no problem where they said there was according to the next two dealers (no marks and comments on the MPI form) and that's still true today. That was it with me and that dealer.

Get a second opinion from a shop

Absolutely. I'm seeing a lot of big ticket item R&R recommendations these days. They have the car up on the rack, they're doing an oil change and the MPI, and they come up with things that are showing no symptoms whatsoever. The A/C thing on this thread has symptoms, though. I recommend YouTubes, Google, other opinions, and talking to friends who know cars as well.
 

Tedjs

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2019 Regal Tourx
Thank you all for your supports!

I too found it difficult to accept the fault is the compressor due to the High Side pressure is Normal.

How can I troubleshoot the expansion valve? Both Low Side and High Side gauges equalized once the engine shut off. What is the pressure switch, and could it cause this issue?

Well, the only way to verify that is to replace it. Again, I am assuming the charge is correct in the system which would require the technician to evacuate and measure the refrigerant amount in the system as this will cause a similar issue.

If the compressor was stuck at a particular displacement then you wouldn't see those readings on the gauges. You can command the valve with a scan tool however if the compressor is mechanically stuck then it won't matter what the valve is doing but that's highly unlikely given the pressures shown.
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2011 Lacrosse CXL AWD
I just read an article on variable displacement compressors and it said that if the cabin temperature is high the low side pressure would be high also. Here's the article. Variable Displacement Compressor
Seems like if the valve was stuck in this position it would be putting out colder air. The article made no mention of what the highside pressure would be. I just googled variable displacement ac compressor and there were a few articles that were interesting.
 

TomB

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Well, have you made any progress?
Thank you, Mama’s Lacrosse, and other supporters, for your inputs. I am still trying to digest all information given here and have not done anything yet. I would like to learn all AC system components and its function for this car. Does anyone have the AC system layout and its components?
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2011 Lacrosse CXL AWD
I've got a stupid question for HotZ28 or anyone else that will answer this for me. Do all Lacrosse's or all Buicks for that matter have auto HVAC systems after 2010? Or I guess what I'm asking is are all A/C compressors of a variable displacement type after a certain year?
 

Tedjs

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I've got a stupid question for HotZ28 or anyone else that will answer this for me. Do all Lacrosse's or all Buicks for that matter have auto HVAC systems after 2010? Or I guess what I'm asking is are all A/C compressors of a variable displacement type after a certain year?

GM has been using variable displacement compressors since the late 1980's on a lot of applications, however the current models use a electronic compressor control solenoid instead of mechanical one. Advantage of them being they do not cycle on and off which causes changes in idle speed etc.
 
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2011 Lacrosse CXL AWD
My 92 Camaro had a pancake compressor if that's a thing. I guess it might be a vane type I don't know. R12 refrigerant was still in use. I wish Ford used a variable displacement compressor on the late model Mustang. I have 06 GT and the compressor really puts a drag on the engine compared to the Lacrosse. Go figure.
 

HotZ28

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I've got a stupid question for HotZ28 or anyone else that will answer this for me. Do all Lacrosse's or all Buicks for that matter have auto HVAC systems after 2010? Or I guess what I'm asking is are all A/C compressors of a variable displacement type after a certain year?
The V5 (variable displacement) compressor was used & available in 1996, not any that I recall before that? The HR6/HD6 was common during the previous years.
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2011 Lacrosse CXL AWD
Thanks HotZ28, I never paid any attention to the type of compressor that was in a vehicle with the exception of my wife's Subaru. I noticed the compressor in her car was way smaller than any I had seen before. I wish someone made a conversion kit or something for my 06 Mustang GT five speed manual. It can get difficult to drive in stop and go traffic. I,m sure it's not all the compressors fault. It's a driver clutch throttle thing. You'd just have to drive it to understand.
 

CorvairGeek

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" The V5 (variable displacement) compressor was used & available in 1996, not any that I recall before that? The HR6/HD6 was common during the previous years."

Those all appear around '85. The load and NVH of the R4 (pancake POS, I own 2 of them) was too much for the new FWD cars, IMHO. The V5 is a wonderful compressor and quite trouble free until GM quit painting them. They corrode and leak at the body o-rings when unpainted.
 

HMTJ6821

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I know that an AC compressor replacement is expensive––I had it done on my 2010 LaCrosse. The diagnosis was that the compressor was not "sucking" strongly enough on the low side. Your observations appear to be similar. I do sympathize with your desire to explore all other alternative causes but consider this; the replacement compressor will come with a lifetime warranty. Of course, this does not cover the labor to remove and replace at a later date.
 

TomB

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LaCrosse
I know that an AC compressor replacement is expensive––I had it done on my 2010 LaCrosse. The diagnosis was that the compressor was not "sucking" strongly enough on the low side. Your observations appear to be similar. I do sympathize with your desire to explore all other alternative causes but consider this; the replacement compressor will come with a lifetime warranty. Of course, this does not cover the labor to remove and replace at a later date.
Thank you, HMTJ6821, and all other Supporters! It is what it is... If it needs to be replaced, will get replaced.

I am still puzzling how can it be the AC compressor intake/Low-Side is inadequate/weak while the High-Side/out-put is fine (not possible if the intake is not available; low in, low out)? The Low-side connector is located before the TXV, could the TXV is restricting (not clogged) refrigerate entering the evaporator coils causing the inadequate cooling issue? And the high PSI of the Low-side registered on the gauge due to the location of the Low-Side connector and before the TXV?
The AC has been blowing out cold air (around 40s F) due to outside temperature dropped to low 80s.
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