a/c compressor

I've never changed an a/c compressor. How difficult is it?

I've never changed an a/c compressor. How difficult is it?


as easy as changing an alternator. take off the belt. take out the 2 bolts that hold the alternator in place.disconnect any electrical connection. and remove the a/c lines. be a bit careful not to break those. make sure to replace the old o-rings with new ones (r134a compatible).make sure to fill in some a/c oil into the new compressor, by filling in from the back and turning compressor by hand.

Do I have to get the system bled? Is oil put in w/ the freon then as well?

If you are changing from R12 to R134a you need to change the oil to a ester oil. Look at a service manual to determine how much oil is required. You usually just put enough in the compressor to do an initial lubrication then inject the rest with the refrigerant. You can buy both non pressurized and pressurized ester oil at your parts store. If you already have a 134a system you need to follow the same procedure for adding ester oil.

Listed below is the EPA law on recvovery, however if you don't have any freon in the system, you can ignor these requirements.

RECOVERY REQUIREMENTS
During service or dismantling of motor vehicle air conditioning systems, containment of the refrigerant is
mandatory. Never open a system without first following proper recovery procedures as set forth by SAE J1989 for CFC-12 and SAE J2011 for HFC-134a. The following procedure will serve as a guideline to refrigerant recovery, always operate the recovery equipment according to the manufacturers' recommendations.
Connect the recovery equipment to the vehicle system service ports. Operate the recovery unit to remove the refrigerant until the system has been reduced from a pressure to a vacuum. With the recovery unit shut off, wait at least 5 minutes to determine if all refrigerant has been removed. If the system returns to a positive pressure, indicating that there is still refrigerant left in the system, additional recovery is required. Repeat the recovery operation until the vehicle A/C system vacuum remains stable for 2 minutes.

Hi there, i too have a 92 pa and im trying to figure out what the trouble is with the ac. when i turn on the ac the air is not cold like ac temp should be, however it is not blowing hot air either thinkin it would be hot if no ac system is workin). is there a way to test the ompressor to suure its not working?.also i just did a conversion to 134from the 12, and my question is is the low line, were thethe ac goes in, is it actually the one closest to the rad, or the one by the tank,by fire wall. if is it the one by the rad, than i need to find a adapter for the inline as the conversion kit i bought doesnt come with one. i would appreciate any feed backk. tyvm in advance.

First, the low side line where you install the refrigerant, is the one going to the accumulator/drier “tank” near the firewall. The high side line on an “ R-12” system in the 1992 Buick takes a special fitting and is usually not included with the cheaper “conversion kits”. You can still get by without using the high side fitting, if you know how to read the low side. Low side should read around 28-32 psi on a stable system, at 80-85 deg. ambient. Also, somewhere in this process, it would be wise to change the high side fitting so you can measure the compressor high side pressure.

When you did the conversion, did you evacuate the system and flush out the old “mineral” oil? Also, did you evacuate the system prior to adding the R-134a and did you add the correct amount of POE or PAG oil in the system? If not, you have a problem that will eventually kill your compressor, if it has not already. The proper flush, evacuation and recharge procedure must be followed, or the system will not cool as expected and also will suffer a premature death!!:uhoh:

A/C systems designed for R-12 have a heavy weight (usually 525 viscosity) “mineral” oil which circulates with the refrigerant and provides lubrication for the compressor. For a system to function properly, this mineral oil must be “miscible” (dissolve in) the refrigerant being used in order for it to return to the compressor properly. R-134a has zero miscibility in mineral oil, so newer oils (mostly PAG and POE) have been developed for R-134a systems. If an R-12 vehicle is retrofitted to R-134a (the oil changed to PAG), sometimes the PAG oil will fail from existing chloride deposits (which cannot be flushed out) from the previous R-12 in the system. POE oils also have their problems, one being low lubricity and another being poor stability (breaks down easily and very moisture sensitive).:screwy:

Hi hot thanks for the feedback, i now know were to put the free on..the fitting closest to the firewall, which today i checked for freeon, and there was nothing. My understanding is that the ac compressor(clutch) WONT run unless there freeon in the system.i was skepticle at first butafter a few test were the guy took the black "power" wire of the switch on the tank and shorted it out, the compressor clutch actually worked!. he did this twice, and both times it worked. if you put the wire back on the tank the compressor did nothing. just wanted to confirm this is actually the way the compressor will come on, with freeon only in. tvm in advance.

Hi hot thanks for the feedback, i now know were to put the free on..the fitting closest to the firewall, which today i checked for freeon, and there was nothing. My understanding is that the ac compressor(clutch) WONT run unless there freeon in the system.i was skepticle at first butafter a few test were the guy took the black "power" wire of the switch on the tank and shorted it out, the compressor clutch actually worked!. he did this twice, and both times it worked. if you put the wire back on the tank the compressor did nothing. just wanted to confirm this is actually the way the compressor will come on, with freeon only in. tvm in advance.
That is right; it will usually turn the compressor on if you jump the low side switch. You are also right to not run it without refrigerant. The "Freon" is what circulates the oil and if it does not circulate, you will kill the compressor.
If the system is empty, you must have a leak that you need to locate and repair. You can inject a can of R-134a with dye, to help you find the leak. You still need to evacuate the system after the leak has been repaired. Also, this would be a good time to install a new drier and orifice/screen.:grinyes:

Do it right the first time, or you will pay for it later!:evillol:

That is right; it will usually turn the compressor on if you jump the low side switch. You are also right to not run it without refrigerant. The "Freon" is what circulates the oil and if it does not circulate, you will kill the compressor.
If the system is empty, you must have a leak that you need to locate and repair it. You can inject a can of R-134a with dye, to help you find the leak. You still need to evacuate the system after the leak has been repaired. Also, this would be a good time to install a new drier and orifice/screen.:grinyes: Do it right the first time, or you will pay for it later!:evillol:


Hey thanks for the good news..thought the compressor was dead!!! one last thing, the air coming in from inside wether it be on warm/cold is the same temp and its not blowing very much at all. i thought i read something about a coloured sensor on the firewall, could this make a difference. tyvm in advance again.

I took my car to a local shop and the problem was the switch. I got one from a junkyard. Fixed it.

I took my car to a local shop and the problem was the switch. I got one from a junkyard. Fixed it.

hi p_dryer, do you happen to know were that partivcular switch is...? also does anyone know of that particular coloured switch thats on the firewall, or is it the same one, that your referring to. tyvm in advance.

Hey thanks for the good news..thought the compressor was dead!!! one last thing, the air coming in from inside wether it be on warm/cold is the same temp and its not blowing very much at all. i thought i read something about a coloured sensor on the firewall, could this make a difference. tyvm in advance again.
I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

Hi hot, as for the first question, no theres really no change in the temp whether its on cold/warm. as for the second question, theres very little change in the flow of air even on hi. ive had this car bout two years, but this is first time ive attempted to use the a/c. tyvm in advance....

Have you followed the previous advice on finding the leaks, evacuation, oil and charging the system? If so, is your compressor cycling normally? Lack of air flow can be due to a restriction in the evaporator or the blender door actuators sticking or being out of calibration.

I replaced the control module on the inside of the car. It didn't look like it could be fixed to me. Thats why you want to get one from a junkyard.

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?
hi hot, im totally baffled here....i just tryed chargin the system, and the compressor came on..for a sdhort time and shut off again. but inside the casr the ac was on and the blower was on..and i put it on full, and it blew full air out. i did notice that when i was trying to charge the system, there was the change in engine movement., and the fans in front of the compressor was also on. but the compressor stayed off. im wondering if theres something else im missing here as im told the compressor, if it was dead, wouldnt just come alive when it choose to. if it dead its dead. could the condenser"tank" switch be faulty perhaps..? could it have something to do with that prevviuosly mentioned switch..? tyvm in advance.

Most of the older cars (pre 96), have a switch in the low pressure side of the system which opens at about 24 psig, cutting off the compressor. The evaporator warms up, and when the pressure reaches around 40 psig, the switch closes again, restarting the compressor. If you are using R-134a and have not changed the switches, the pressure is still set for the R-12 system!

You did not mention whether or not you had cool air when the compressor was on, so I have to assume that you did not. Based on that assumption, it sounds like you have a blocked orifice screen in the high side line. Usually, a blocked orifice screen is caused by internal compressor failure often referred to as “black death”! This condition will exist when the orifice screen is blocked and the refrigerant can not pass through the orifice. Low side pressure will usually never drop below 50 to 60 psig and the high side pressure could rise above the switch limit, thereby shutting down the compressor.

Also, when the AC is selected on the ACC control pad, the radiator fan should turn on and the engine RPM should increase. If you have a blocked orifice screen, the compressor will make some abnormal noise and it will seem that the engine is struggling to operate the compressor. I.E. noise, vibration etc. :crying:

You need to take your car to an AC shop that can diagnose the problem using the proper equipment to test the high and low side pressures!:grinyes:

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

Hi hot, ok took my car into shop, and was told by2 independant ac mechanics that my compressor was shot(one got a reading of 80-30, the other put a stethoscope on the compressor and told me there was a leak in it, his lil machiny went off). ok my question is this. is it that difficult to take this compressor out, or does a specialized mechanice need to do it. if i can do my self id like to, u have any feedback on whats all involved in taking it out. tyvm in advance.

http://http://www.automotiveforums.com/vbulletin/showthread.php?t=555021

Some recent discussion in the link above on compressor R&R in the LeSabre forum, same procedure applies here!
You will need the proper equipment to evacuate, flush & charge the system. The orifice screen is in the high side line coming out of the condenser. You must change that and the accumulator/drier also! Do not, and I repeat, do not :shakeheadtry to change just the compressor without the other components along with proper flush and evacuation!! If you do, the new compressor will fail "sooner than later"!!:crying: You could flush the system (if you know how) and replace all the parts, then take it to the AC shop for evacuation and charging.

Another link with some good info:http://www.automotiveforums.com/vbulletin/showthread.php?t=570474

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?
hi Hot, ok i had the compressor put in professionally, but the air still doesnt work. the compressor comes on, however the clutch does not. the guy who put it in thinks its the switch, any ideas on this oner..tyvm in advance.

Did your mechanic reset the ACC controller so you do not have a flashing light on the temp display when you start the car? If so, you need to verify whether or not you have a full 12V to the clutch coil assembly, when the controls are set for AC. I am surprised that the mechanic did not check that! Have him check it for you, if you are not familiar with the procedure.

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently? Hi Hot, yes he did reset the acc control, so theres no flashing light. he did tell me i could try the relay switch, as he says theres NO power, after the black switch that goes on the condenser. He beliefs its in between the ac button in the car, and that black plug that goes onto the condenser. as for checking the voltage to the compressor, he did not. he did tell me the ac went on for bout 5 min, and shut off. tyvm in advance.
Is the relay switch for the ac second to the left on the passenger side...theres two on the left side, and 3 on the right side...

Relays, in order left to right on the ACC system;
A/C
Horn
Blank
Blank
ABS pump
ABS main
High cooling fan
Low cooling fan

If you want to test the relay, just change it with one of the others, they are all the same type. There is not a "black plug going to the condenser" you must be referring to the compressor? Did the mechanic flush the system, change the orifice screen and accumulator and suck down the system?

Relays, in order left to right on the ACC system;
A/C
Horn
Blank
Blank
ABS pump
ABS main
High cooling fan
Low cooling fan

If you want to test the relay, just change it with one of the others, they are all the same type. There is not a "black plug going to the condenser" you must be referring to the compressor? Did the mechanic flush the system, change the orifice screen and accumulator and suck down the system?


Hi hot, the relay switch was the problem, ac now working. thanks. what im wondering now is the amount of cold air cooming out of the vents isnt in my opion very high. i even switched the relay switches for them thinkin it might be that. is there anything else i can look for as for air flow, im not complaining, just wondering if air flow can be more significant. tyvm in advance. i surely appreciated all ur help hot.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/297374ACC.jpg (http://www.automotiveforums.com/vbulletin/%5Bimg%5Dhttp://files.automotiveforums.com/gallery/watermark.php?file=/503/297374ACC.jpg%5B/img%5D)
On your ACC controller, you have "auto" fan control and "high & low". See pic above. (Lower row, three buttons in the middle). You can override the auto by pressing "high" to increase fan speed or pressing "low" to decrease speed. You do not have "relays" for the AC blower on the ACC system; it uses a solid-state control module. Run your fan up to “high speed” manually and see if the air flow is any better. If the fan is set in the “auto” mode, speed will increase & decrease, based on feedback from the network of sensors in the ACC system.:screwy:

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

Hi hot, ok i did what u said, actually done this already previuosly...is it possible the passage ways are partially blocked by foreign debris(nest,etc). if so would blowing air in from the inside to outside eleviate this...?im running out of thought/ideas here...has this ever happened to you..? the blown air can only be felt til in behind the sterring wheel..and itsnot powerful either....tyvm in advance.

You could have a partially blocked evaporator or, blender door actuator malfunction. Turn the system off-on several times in paused succession while listening for a clicking sound coming from under the passenger side dash. It is not likely that you have a "rodent nest" in the evaporator box, however, you could have "tree trash" or other debris blocking the air flow. Could you describe the air coming out of the vents as, "cold"?
You will have no luck trying to blow air from the "inside to the outside".

hi hot, as for the air it is cold. i will see if the guy who installed it can have a peak at what u were refering to, before i start diggin around for tree stuff. tyvm in advance. i guess i should be greatful for what i have for cold air..now.
Ok, i have spoken to him bout that blender door actuator, and hes telling me that its an eletrical problem, once again. is this true. and if so how , what do i do, as he says its beyond his professionlism?...beginning sounds like the tree thing would be easier to fix!!!

the blown air can only be felt til in behind the sterring wheel..and itsnot powerful either....tyvm in advance.
Are you saying that you do not have air blowing out the dash vents and that it is blowing out the defrost & floor vents?:sunglasse

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

Hi hot, sorry i havent gotten back to you in couple days, i was waiting on the guy who put compressor in to floow up and "go inside and have a look" at the area of the actuator door and soon to see if it was some how being restricted. his other suggestion if it wasnt blocked was gettin another control panel, and trying that. well hes being sick, so my thought was if its not to hard i can try doing that, looking into the inside of the actuator area, under/behind the the dashboard. what im wondering is were do i start, if i attempt this?....is it as simple as taking out the compressor?..or way more to this procedure. maybe u have some tricks upo your sleeve for this?..tyvm in advance.

I am sorry, but this job is not for the novice DIY home mechanic, or those who are willing to try, however, “wondering is were do i start”. :shakehead Also, if your mechanic has made it clear, “it’s beyond his professionalism”, I would suggest that you find someone that has experience with the Buick ACC system, otherwise you will be just paying for “changing parts” until the problem is resolved! Again, this is a very complicated system to understand and diagnose with its network of electrical sensors, actuators, programmer and control panel. And finally, if you or your mechanic, do not have a factory shop manual to go by, or experience with the system, it would be best to take it to a professional.:grinyes:
(Dealer or AC specialist)?

Hotz28, when you mention how complex the a/c systems in Buicks are, I am just curious now if the systems in olds, pontiacs, chevys and caddies around the same era are just as difficult to work on, or does Buick have its own particular system making it distinguishable from other GM vehicles? I

Basically, all GM Auto Climate control (ACC) systems have the same functions with only minor differences between the makes and models. This is not to say, “They are the same”, however the operation is similar.

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?

Hi hot, ok..thanks for the help on the acc, i will try and get that guy to look again, when he feels better(he was just gonna look to see if there were restrictions inside), possible eliminating an electrical issue. he did say that he felt some air coming out the bottom of the acc (the black plastic housing on the floor), which he said could be contributing to air flow loss. he was gonna check this out. i put my hand down there afterwards to see if i cvould feel, but could not. guess he knew what he was looking for. hoping that its a restricto problem as opposed to a time consuming electrical issue. also is it possible to have an inefffective acc control panel(still comes on but not full efficiency), or is it either it works or it dont. tyvm in advance.

I assume that you have auto climate control (ACC)? If you do, does the temp stay the same, no matter what temp you select? Also, can you feel any change in air movement when manually moving fan speed up or down? There is a "sun sensor" on the dash that has an affect on air flow through the vents on the ACC system, if that is what you are referring to, however, it is not likely to be your problem though. How long have you had this car and did this problem just appear recently?
Hi, ive come up with a temporary solution for the rest of the summer, and it costs under 30bucks. theres a fan(sensor) thast runs of solar that supposedly cools your car to about 75 degrees, and that and with current cooling should be ok, espeially if this problem turns into a much bigger(costwise) problem. thanks.