2010 Lacrosse ac clutch not disengaging

coolmeiser

Buick Newbie
5
1
3
Buick Ownership
Buick
This spring my Lacrosse CXL 3.0l air conditioning decided to start acting funky. Pressures are 44 and 185 No cycling observed at gauges. Clutch never seems to disengage, wont even turn with engine off and key removed. Climate control doesn't cool the car adequately on the highway (moderate hit and miss cool air) and blows warm air in town even set on max cool. I'm no trained mechanic but would expect the clutch to be disengaged and turn with out using a cheater bar on it. Haven't tried that yet... Unless one of you more educated fellows can enlighten me, I'm looking at a compressor swap including dryer replacement and system flush. I've done it on my former Taurus SHO so it's not out of my skill set, I just flat out don't want to if i'm missing something simple if you know what I mean.
 

Rich B.

Active member
441
71
28
Minot, ME
Buick Ownership
2016 LaCrosse & 2013 Boss 302 Mustang
The twin fans cool the radiator? Or the fan for evaporator, may be 2, I can’t say on that.
______________________________
 

2007LucerneCXL

Full Member
2,541
749
113
Illinois
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
The low pressure switch may be bad and is keeping the clutch engaged, just another option to consider. Sorry I don't have any information on how to test it.
 

coolmeiser

Buick Newbie
5
1
3
Buick Ownership
Buick
Did you try to put the heat on full hot to see if the clutch disengages ?
Unfortunately heat works wonderfully... Thanks for the thought
I’d try first operating the compressor solenoid with a direct 12VDC as problem may be with temp control instead (should be located with evaporator fins. Can just picture a compressor change, recharge and still not working?
Applied 12vdc to the solenoid (located on bottom of compressor) with no change in symptoms.
______________________________
 

HotZ28

Full Member
7,025
308
83
Buick Ownership
1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
The compressor is known as an PXE16, similar to the V5 in that is a variable piston stroke compressor which has no clutch cycle off/on when the A/C request from the control is on. What was the ambient temp when you checked high/low side pressures? My best guess is, that the low side seems to be on the high PSIG side of the scale, which would indicate low refrigerant. More info about the variable stroke compressors in the link below.
Variable Displacement Compressor
______________________________
 

Attachments

Rich B.

Active member
441
71
28
Minot, ME
Buick Ownership
2016 LaCrosse & 2013 Boss 302 Mustang
Interesting, this is similar as far as the compressor remains engaged either way. Compressors for air tanks sometimes run continuous with load engaged and free wheeling through mechanical pressure switch, before the electronic idea.

Learned something new here also, good topic.
 

CorvairGeek

3.8L Member
239
55
28
The Gem State
Buick Ownership
1996, 92 Buick Century
The Sanden compressors with electronic refrigerant control can have poor cooling like you are describing too. They can be erratic in cooling. Turning them off and all can create different rates of cooling, as seen when running and watching the gauges (depending on what the failing valve does each time, besides the dynamics of a variable displacement compressor). Be very careful if adding refrigerant. GM only recommends charging by weight, and has for decades.
While it is extremely refined and great for NVH, the phrase a 'boar with teets' comes to mind.
 

coolmeiser

Buick Newbie
5
1
3
Buick Ownership
Buick
looks like ill be taking the car into my local mechanic to have the refrigerant evacuated and, hopefully weighed to see how much r134 is in this car. will update when I have more info.
 
Top