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Discussion Starter #1
If any of you have seen my newbie thread then i bought my g8 knowing that the A/C didnt work and i was told that there was probably a leak somewhere. I was told that it was charged up and then nothing. I took it to the dealer yesterday and oh course the worst thing it could be, they told me the compressor is bad. The system is full of refrigerant and i think they said it kicks on but it just doesn't pump anything so they suspect that something is broke inside.

They said it would be $1275 for one. I oh course said i would pass. Gmpartsdirect has it for a little over $500 after shipping and i would save another $400 installing it myself.

Has anyone ever changed one out? Is it a real pain or need special tools or is it pretty straight forward? Thanks you guys.
 

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Well I have not done one on my g8.. but I have on other cars.. first thing first.. have a shop recover the R134a so the system is empty.. after that its just mechanics 101.. be careful not to tear O-rings or just replace with new on the lines running to compressor.. after that take back to shop and have them vacuum system. that get the moisture out and makes it easier to recharger.. they will have to add PAG oil when recharging
 

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This is sad to hear. I think most disagree with me on this, but my contention is that the compressor spins all the time *if* the engine is running. It just isn't making any cold air *if* there isn't a current request for it to do so. Once a demand for cold air exists, a slick device within the compressor is commanded to move to a position that will produce X amount of cold air to satisfy the temp setting request by the operator (anywhere from no cold air to max amount of cold air) that the compressor is capable of putting out.
To protect that compressor from exceeding the max allowable system freon PSI rating, or sensing total loss of all freon, is a pressure switch located alongside the compressor on the high pressure line out. If it fails, the compressor *will not* make any cold air. That pressure switch would report a fault code to the ECM of either P0532 or P0533. These codes *will not* turn on the MIL light. So you would have to go looking for it in the first place (nothing tells you on the I/P that anything might be wrong on this one).
I would make sure that neither code is recorded into memory. If the system is known to be full of freon (but inop) you at least deserve to eliminate that pressure switch as a source before having to spend the big bucks.
It says that you have to remove the air dam and attack the removal of the compressor from underneath. It doesn't appear to be much of a problem. I'm thinking that if you know of a good AC shop, you could have them recover the existing freon, and after the compressor R&R, they can evacuate the plumbing (to verify no leaks of any kind) and then re-service the system. Might save some bucks there (in effect *you* supplied the freon). It would also be smart (I think) to *not* reinstall the AC belt until the system is re-serviced. This way the compressor does not rotate until you've reloaded up with freon and oil. If all is good, then reinstall the air dam. Long read I know, but its the way I would go about it.
 

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doesn't the system only have one belt? if you didn't put it on till after the a/c system was full again.. you would be driving with no water pump, power steering, alternator.. and the compressor clutch spins all the time.. not the internal pump.. it only kick on when the a/c system tells it to, via controls and pressure switch
 

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doesn't the system only have one belt? if you didn't put it on till after the a/c system was full again.. you would be driving with no water pump, power steering, alternator.. and the compressor clutch spins all the time.. not the internal pump.. it only kick on when the a/c system tells it to, via controls and pressure switch
AC has its own belt.
 

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Discussion Starter #6
This is sad to hear. I think most disagree with me on this, but my contention is that the compressor spins all the time *if* the engine is running. It just isn't making any cold air *if* there isn't a current request for it to do so. Once a demand for cold air exists, a slick device within the compressor is commanded to move to a position that will produce X amount of cold air to satisfy the temp setting request by the operator (anywhere from no cold air to max amount of cold air) that the compressor is capable of putting out.
To protect that compressor from exceeding the max allowable system freon PSI rating, or sensing total loss of all freon, is a pressure switch located alongside the compressor on the high pressure line out. If it fails, the compressor *will not* make any cold air. That pressure switch would report a fault code to the ECM of either P0532 or P0533. These codes *will not* turn on the MIL light. So you would have to go looking for it in the first place (nothing tells you on the I/P that anything might be wrong on this one).
I would make sure that neither code is recorded into memory. If the system is known to be full of freon (but inop) you at least deserve to eliminate that pressure switch as a source before having to spend the big bucks.
It says that you have to remove the air dam and attack the removal of the compressor from underneath. It doesn't appear to be much of a problem. I'm thinking that if you know of a good AC shop, you could have them recover the existing freon, and after the compressor R&R, they can evacuate the plumbing (to verify no leaks of any kind) and then re-service the system. Might save some bucks there (in effect *you* supplied the freon). It would also be smart (I think) to *not* reinstall the AC belt until the system is re-serviced. This way the compressor does not rotate until you've reloaded up with freon and oil. If all is good, then reinstall the air dam. Long read I know, but its the way I would go about it.
sorry im normally quicker at responding, ive been on the forum but was never informed of more posts. that sure sounds like the way to go, should i reset everything by unplugging the battery, if thats the correct recommended way, and see if that code or codes set just to be sure? reset and try turning on the ac everytime i go to work and see if it sets?
 

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You can force a reset that way, its just not my way. I would want to see any faults that might be current or in history right now. Then if no solution to a particular problem is obvious due to all codes found, then I would erase everything an start a new. Then whatever fault or faults pop up, it might lead to the most obvious thing that bad.

Your not going to know *if* the pressure switch is bad unless a fault code reader shows either one or both of those codes. Yes you can clear everything, retest the AC an if it continues to fail, it might then again log in an important code or codes that will tell you what you should TS. An of course it still *could* actually be a faulty compressor. There have been a couple of outright compressor failures that I remember reading about. My take, is that you should attempt to TS as much as possible, before having to resort to a compressor change, if there's any chance of saving the OEM stuff.
 

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Discussion Starter #8
You can force a reset that way, its just not my way. I would want to see any faults that might be current or in history right now. Then if no solution to a particular problem is obvious due to all codes found, then I would erase everything an start a new. Then whatever fault or faults pop up, it might lead to the most obvious thing that bad.

Your not going to know *if* the pressure switch is bad unless a fault code reader shows either one or both of those codes. Yes you can clear everything, retest the AC an if it continues to fail, it might then again log in an important code or codes that will tell you what you should TS. An of course it still *could* actually be a faulty compressor. There have been a couple of outright compressor failures that I remember reading about. My take, is that you should attempt to TS as much as possible, before having to resort to a compressor change, if there's any chance of saving the OEM stuff.
yeah i remember you saying the light wont come on but i do have a superchips cortex that im pretty sure read codes.
 

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The odd thing here is that every failure of an AC compressor on a G8 that I have heard of is accompanied by noise. To have one fail and make no noise seems electrical (to me). Check those codes...If the low pressure switch is bad, you can save yourself ALOT of time and effort.
 

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Discussion Starter #10
The odd thing here is that every failure of an AC compressor on a G8 that I have heard of is accompanied by noise. To have one fail and make no noise seems electrical (to me). Check those codes...If the low pressure switch is bad, you can save yourself ALOT of time and effort.
I bought the car about 2 yrs ago from a guy that has a place that flips cars, they replaced a few things, condenser i know was one thing so i figured there was a leak. I dont think the compressor was replaced nor was there any indication on their part that it needed to be changed. It appears to spin freely and no noise, and the belt is there. Quick read with my superchips cortex and a buddys personal scanner came up no codes. I guess i need to take it to a professional place with their scanner. Not sure if the dealer ever thought to check this. I still have my fingers crossed
 

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My compressor failed without any noise. it was the clutch on the front of the pulley that broke.
 

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Discussion Starter #12
My compressor failed without any noise. it was the clutch on the front of the pulley that broke.
And unfortunately im sure you have to buy a new compressor either way am i right? No replacement clutch for it
I still havent have time to take it anywhere, everywhere is always closed after i get off work, hopefully tomorrow.
 

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ac compressor

i have the new clutch, just haven't had time to see how to put it on. i am pretty sure i can change it in the car
 

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Discussion Starter #14
i have the new clutch, just haven't had time to see how to put it on. i am pretty sure i can change it in the car
Oh really? Can you take a picture of it? Does it have a part #? At this point im not sure what to do, i guess i need to scan it for codes and after that im not sure. I feel like im going to get lucky and it be that pressure sensor or im going to end up throwing a lot of money trying to figure it out.
 

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Discussion Starter #16
Thats weird bc the exploded view of the ac system on gmpartsdirect doesnt even show that as a separate part. Im going to have it scanned monday and go from there. If there are no codes ill prob take the compressor off and inspect it
 

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Thats weird bc the exploded view of the ac system on gmpartsdirect doesnt even show that as a separate part. Im going to have it scanned monday and go from there. If there are no codes ill prob take the compressor off and inspect it
Codes for what? Only a tech 2 or high end scan tool will read HVAC codes, and compressors don't normally throw codes (at least I've never seen it in my 4 years). If the compressor is bad, it's bad. A set of gauges on the A/C system will verify it is not making pressure. They can not be rebuilt economically, replacement is the typical route.


Before you dig into this too far, get a test light. Unhook the coil plug from the compressor. Turn A/C on inside the car with engine running. With the test light grounded see if one of the pins has power. If it does, move the test light clip to battery hot. Check the other wire. If it lights up as well, you are good electrically. If one of the wires does not light the test light with it hooked to either power or ground, you have an electrical problem somewhere.
 

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Discussion Starter #18
Codes for what? Only a tech 2 or high end scan tool will read HVAC codes, and compressors don't normally throw codes (at least I've never seen it in my 4 years). If the compressor is bad, it's bad. A set of gauges on the A/C system will verify it is not making pressure. They can not be rebuilt economically, replacement is the typical route.
Codes that the pressure sensor being bad would set, therefore no ac
 

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You'll still need more than an autozone scan tool to read that. I thought to previously said the compressor was kicking on just not building pressure?
 

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You'll still need more than an autozone scan tool to read that. I thought to previously said the compressor was kicking on just not building pressure?
Yeah i know but i figured it wouldnt hurt to try and use my cortex first and it said no codes. Have to go monday bc everywhere is closed.
 
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