View Full Version : HOW TO: Step by step A/C compressor replacement

07-27-04, 09:42 AM
Good morning everyone. I changed the A/C compressor on my 95 STS this weekend and tough my experience could help others. So here is a step by step to A/C removal. Not a very hard job but the space is kind of tight!

#1 Have the A/C system evacuated by a shop or a dealer
#2 disconnect the negative post of the battery (safety first children!!!)
#3 Jack the car, I used a ramp on the driver side then floor jack and stand on the passenger side
#4 Remove passenger side front wheel
#5 Remove the front plastic shield in the wheel well (3 Phillips screm) and the plastic cover behind it (10mm and 8 mm screw)
#6 Undo the accesorie belt by inserting a 1/2 breaker bar into the tensioner and pulling toward the front of the car
#7 Remove the front shield underneath the car, this is the plastic shield in front of a large beam that run accross the car
#8 Now the dirty part! Go underneath the car and remove the oil filter
#9 Remove the rear bolt of the compressor. This bolt is located right next to the oil filter. You acess is with a deep socket and an extension inserting the socket trough the front (shield removed) between the A/C line.
#10 Remove the 3 front compressor bolts trough the wheel well.
#11 Undo the bolt holding the A/C lines. To do this you will probably need some help. Ask your friend to pull the compressor in the wheel well while you are underneath the car to get extra room, I did it with a pry bar and a floor jack to hold it in place. The bolt is between the 2 lines (14 or 15 mm) I recommend the use of a low angle wrench!!! the angle is so limited that I could only get 1 or 2 click out of my regular ratchet
#12 Pull the compressor trough the wheel well, undo the electrical connection !!!Success!!! the compressor is out
#13 Manual recommend that you put the same amount of A/C lubricant in the new compressor has there was in the old one. Mine was bone dry so i putted 4 oz (dont quote me on this, manufacturer recommends 5 oz, GM tech recommends only 2 oz) Put the plug that came with the new compressor so the oil wont spill everywhere
#14 Remove the bracket on the rear of the old compressor (2 bolts) and reinstall it on the new one
#15 Insert the new compressor trough the wheel well
#16 When i did mine i did NOT plugged back the electrical connection or the hose that connect to the compressor. I did not want to contaminate the new compressor with metal shaving from the old one. I can't see any other way to replug the lines then to remove the compressor but the dealer tech managed to do it, dont ask me how!!!
#17 Insert the 3 front bolt loosely
#18 Insert the rear bolt tightly
#19 Tighten the 3 front bolts
#20 Reinstall the oil filter, this might be a good time for an oil change since you are already underneath the car!
#21 Reinstall the belt, this is a good time to install a new one because you have easy access to the lower pully trough the wheel well.
#22 You will also need to change the dryer (most A/C compressor warranty ask you to do this to have a valid warranty!!!) The dryer is the metal can sitting "in" the coolant tank. Just one bolt to remove and 2 A/C lines. DO NOT unseal the dryer before rechargin the system!!! you will ruin the moisture absorbing property of the dryer if you do.
#23 Reinstall the plastic shield, wheel, reconnect battery

After this I brought my car to the dealer and had them flush and recharge the system, and replace the orifice tube.

TOTAL COST: (in Canadian dollar including taxes)

Dealer flush 130$ including diagnostic of the blown compressor
A/C Compressor 119$US + 30$US s/h + 67$ tax and UPS charges = 270$ CAN from EBAY
Acc. Belt 31.50$ @ Canadian tire
Dryer 121$ @ GM dealer
8 oz oil PAG-150 23$ @ Local jobber (dont got to AutoPart Extra, they charge 36$!!!)
Dealer recharge 236$ Including Replace orifice tube labor 49$ Orifice tube 4.85$ Oil, dye, refrigerant and labor 150$
TOTAL: 815$

ESTIMATED DEALER REPLACEMENT COST (excluding taxes) from Boulevard Chevrolet Oldsmobile Cadillac Ltée in Hull, Québec

A/C Compressor 1000$ new OR 600$ rebuilt @ Dealer OR 392$ rebuilt @ Canadian Tire
Acc. Belt 45$
Compressor labor 315$ 3.5 hours @ 90$
Flush labor 180$ 2.0 hours @ 90$
Recharge and etc 150$

TOTAL: Between 1300 and 1800 with taxes depending on the compressor

I hope this will be usefull!!! and dont hesitate to correct me if I was wrong on some point

07-27-04, 11:16 AM
Thanks for the step-by-step. Very helpful! I will have to be doing this sooner than later, hopefully while it's still warm outside. :bonkers:

07-27-04, 01:47 PM
JS, you hit the nail square on the head! I just did the compressor on my '95 Eldorado yesterday. You beat me to putting this post on (Wish it would have been on here yesterday!!!) The only thing I did differently was I didn't remove the oil filter (I'm a glutten for punishment) But I can see where that would make it easier!! Like you said, it wasn't hard/just very tight working quarters. My local shop was asking $1100, and I was able to get it done for just under $500. :bouncy:

07-27-04, 02:23 PM
Ya the oil filter is not really in the way but can help to free some space, and every mm available is required here!!!

Remove the oil filter EARLY in the job and let the housing drip, it can drip for quite some time and I had some oil drip on my forehead, mouth, glasses etc... not very pleasant :rolleyes2

07-28-04, 01:54 PM

09-07-04, 02:05 AM
I just wanted to thank JS for his incredibly helpful guide to what was a scary little project relative to someone who has never done anything with front drive cars. I have a 96 and 97 Deville, but up till now, they havent required much other than brakes!.....I thought Id offer a little additional info:
1. I bought a rebuilt compressor from icecoldairparts (which is the ebay screen name) on ebay for $150 shipped which I thought was an excellent price.....as a bonus, it also worked.
2. I shopped and bought the dryer online for under $50 shipped.
3. I had an "O" ring kit, but the double ring system used on each side of the dryer used rings that are much thinner walled than the old style.....need a new kit.......Wound up getting them from a Ford dealer!
4. If your compressor failure wasnt catastrophic (mine was just leaking out the shaft seal) there is really no need to replace the orfice tube....even when Ive had compressors fail big time, most of the time the filter screen on the tube usually never fills up appreciably....Ive cheated on this dozens of times and gotten away with it. Also, I have used add-on inline filters occasionally when the situation looked shaky, but have NEVER EVER flushed an auto a/c system and have never had a problem. If you're not using junkyard parts, and you keep the lines clean as you are disassembling them and working on them, and you didnt have some sort of chemical catastorphe like wrong oil mix, this flushing obsession is overkill.....Im not in the business, but have done dozens of compressor replacements and three times as many other problems resulting in having to recharge. I dont think it was from luck alone that my success rate has been 100%.
5. Anyone doing this job (the hard part) should spring for the a/c tools and charge the thing themselves.....for the price of having it done "professionally" you're almost there.....The auto parts store has a manifold gauge set for around $100 (even less on ebay), 8 oz of oil is under $10 at autozone (Im not sure how that $35 price found you), you can still buy R134a at Sams Club for just over $125 for a 30 lb cylinder (you need 2lbs to charge the system), and I got my vacuum pump off ebay for around $150. New ones are about $250. Then you're good to go for all your auto a/c needs!
Charging takes less than 2 hours, and requires that you hold a vacuum on the system for over an hour. If you want to get fancy, you can buy a vacuum gauge, but if you have your pump tested, and know that it is pulling less than 150 microns (or so), the meter is not necessary. Manifold gauge connections are now polarized so you cant screw them up anymore.....The "danger" in doing this is mixing up the high and low pressure sides relative to filling....Always add refrigerent thru the low pressure side (blue). Reversing this exposes the canister of refrigerant to a potentially explosive pressure from the compressor....other than that, wear eye protection, long sleeves, and you're pretty well set to go.....once you get comfortable with it, its a no brainer.
Add r134 using the manifold gauge and a bathroom scale to tick off a few pounds. Or, you can just buy little cans with a fill hose and measure/fill it that way. I used Cooltop refrigerant for the first time, which is a 134 compatable gas that is supposed to work a bit better, and does. I also always put in a can of "tuneair" which is a drying agent that pulls moisture out of the PAG oil and converts it to a harmless silicone so the system runs water free. PAG oil is a moisture sponge, and was a step backward in a/c technology. PAG oil combines with water to form a corrosive that destroys the system from the inside....a perfect selection of materials for this application! When the system is open during servicing, the oil can absorb enough moisture to get you in trouble. Also, PAG oil off the shelf can be contaminated......be sure only to buy metal cans that had the lid on tight!

09-07-04, 08:27 AM
Flushing the system and changing the orifice tube seems to be cheap insurance for me!!!
I wanted to do the whole thing myself but could not find a can of refigerant in Canada?!? no local store would sell them to me, most of them told me its illegal. Any way beem a couple of hot summer months since ive installed it and it still works great!!! Now i just have to get rid of the funky smell lol I think ill just buy a cleaner / deodorizer can at Canadian tire, it worked great in my old Sunbird.

04-06-05, 07:15 PM
When you say "DO NOT unseal the dryer before rechargin the system!!! ". Do you mean you have to charge the system and than replace the dryer? Also where is the orifice tube located im having a hard time finding it.

04-07-05, 08:01 AM
The dryer removes the moisture within the line, if you open it in advance it will just soak up moisture from the atmosphere and wont be able to work properly afterwards. You need to reconnect it to recharge the system. The dryer is the aluminium can sitting on the passenger side wheel well next to the coolant overflow tank. I dont know where the orifice tube is located, i didnt bother looking for it since i had the car recharged at dealership.

04-07-05, 08:10 AM
Its been almost a year since I wrote this guide. Here are some updates: the compressor works fine but the clutch is starting to make some horrible noise. I contacted icecoldairpart (ebay member) about the one year warranty. They told me I have to send them back the COMPLETE unit (compressor + clutch).... in ORIGINAL bag and box (who keeps a cardboard box after 10 months?). They told me they cannot just replace the clutch because they only have complete units... anyway i saved a bunch of $$$ with this refurd compressor so im not mad, but i wont use the warranty, I will simply replace / have replace the clutch with a new unit. This seems like a lot less trouble then purging/removing/reinstallint/recharging the system and have anothey refurd compressor/clutch that can fail. Ill just bite the bullet and pay for a new clutch.

Conclusion: icecoldairpart has good prices and decent quality refurd compressor but "tricky" warranty.

04-07-05, 12:33 PM
When you say "DO NOT unseal the dryer before rechargin the system!!! ". Do you mean you have to charge the system and than replace the dryer? Also where is the orifice tube located im having a hard time finding it.
The orifice tube is located in the A/C line that runs along the firewall between the high and low pressure sensors. You'll find a diagram in this thread.

07-14-07, 09:13 AM
I've just done this for the second time in 2 months on a 97 seville and while this guide helped, for me there are a few differences.

1) Take off the serpentine belt,disconnect the negative battery terminal & loosen the lug nuts on the front passenger side wheel.

2) Raise the passenger side of the car and place a jack stand right on the front corner of the frame.

3) Remove the the front splash guard then the oil filter and while the oil drips out remove the tire you loosened & then take off the two splash guards behind it.

4) After the oil stops dripping remove the bolts holding the oil filter adapter to the engine. One bolt is accesible through the oil filter hole the other you need to use a socket with an extension coming in through the space where the front splash guard was removed. Once thats done move the adapter out of the way.

5) At this point you will have clear access to the bolt holding the tubes on the back of the compressor as well as the bolt that holds the rear bracket to the engine. Remove the bolt holding the tubes first (15mm I believe) and then the bolt holding the bracket (10mm)

6) Next, in the wheel well loosen the left side nut but dont remove yet. Remove the right side bolt & then the top bolt. You will need to use one hand to keep the compressor from leaning while removing these two bolts. After that remove the nut you loosened first. All three are 15mm.

7) Pull the compressor towards you until you can see the electrical plug. Unplug it and then remove the compressor. Once out remove the rear bracket from the compressor.

Total time about 1 hour, an hour and a half tops.

01-10-16, 02:37 AM
Do you use a suction line filter as well as the high pressure in line filter you referred to in your post? If so, have you had any problems with leaking refrigerant from the filter?

If you put in a new drier, I've read you should also add pag oil to it. You didn't mention it so I was wondering if you have some other experience with this?

You are asking questions of members who have not been here for 11 years. Please note the post dates before digging up old, dead threads. Ask questions in the proper vehicle forum, not in Tech Tips. Thank you.