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DIY: A/C Compressor removal and replacement

118K views 46 replies 31 participants last post by  burntoutrubber 
#1 · (Edited)
This is a DIY on the removal and replacement of the Air Conditioning Compressor. I am offering this as a guide and maybe complete or missing information that I consider common sense or I expect people to already know how to do. I am not responsible for any damage you cause your car by doing this DIY. If you decide to do this good luck and I hope it goes well.

I have been working on cars since I was 13 years old and helped my dad restore a 1966 Jaguar Mark X. I also owned an automotive repair shop and what I am doing here is exactly how I would do a client***8217;s car if it came in with this problem.

First let me tell you what happen to my car. I replaced the Evaporator to my car (I did not do a DIY for it, but I posted pics in the forum) and about two weeks later the compressor failed. What the compressor did is locked up and it did it so hard it shut my car off. I turned off the A/C switch and kept on driving until I could buy a new (reman) compressor.

Second the parts and equipment you are going to need is important. Here is a picture of what I bought.
List of needed items: A/C Compressor, Receiver/Drier, and as an extra an Inline filter.

I am going to do a separate DIY on how to install the Inline filter. I recommend this little item makes a difference.

I went ahead and removed all of the Freon by connecting it to an A/C machine. This machine is a must (you can go to an auto shop to have them do it) it is illegal to dump Freon into the air. This machine recovers the old Freon as well as vacuum and recharge.

I went ahead and removed the Belly Pan (I had use of a lift makes the work real easy.lol)

Since I had removed the belly pan You can see the Bad compressor and the Belt Tensioner. Using a tensioner tool remove the belt. The arrow points to the 16mm. nut you attach to the tensioner and remove belt.

I then lowered the car and went to work on getting all of the junk off the top.

You should remove the headlight to get access to the Receiver/Drier

Remove the two 6mm Bolts. Remove the drier but do not replace it yet. You will do this later.

Next go for the removal the two 6mm Bolts that hold the A/C lines on the Compressor.

Here is a Technicians tip for you. Tap the allen tool with a hammer (lightly) into place so it is completely into the allen head. I use socket allens.

After removal of these two bolts you are done for the moment on top of the car. Time to get under the car.

Remove the three bolts and take compressor off of the car.

This is the crucial part of any A/C job. With the Compressor and the drier out you need to flush out the A/C condenser and Evaporator. This really is crucial. I used an alcohol based A/C flush to do this. Here is a picture of what I use to flush out the system. You fill it with flush connect it to air line then put the nozzle on the line that feeds the condenser and spray away till it all comes out clear and no more oil, flush and dirt. You should do it twice at least. Make sure it comes out clean.

Sorry no pictures of me doing the flush. But here is a picture of what was once a blue clean rag covered in dirty oil after the flush. I recommend putting the rag around the opposite line that you are flushing so you don***8217;t make a huge mess.

When you are done with all the flushing go ahead and install the Compressor in the car, just like you took it off. My compressor came filled with oil so I left the cover plates on it so I would not spill the oil. The compressor came with 8 ounces of oil in it. Once you have put the three bolts in go ahead and put the belt back on and the belly pan, you are done under the car.
Now lower the car and install the Drier and A/C compressor lines (lube the new o-rings with a/c oil makes it easier to go in.)

This is the old compressor (I shook the compressor and it had loose parts in it, Threw a rod Internally). I hope this picture helps you understand the compressor set up. Do not forget to reinstall everything you removed to do this job.
The final part to do is Vacuum the system ( I did it for an hour, Florida is humid) and then I went ahead and charged it. The machine I used does everything from one machine and I doubt any of us have one of these at home (they ain***8217;t cheap.lol).

This DIY should give you a full idea of what it takes to do the A/C work and get your car back in the cold. I finished it and now have A/C again. This is not an easy job, but it can be done.

Good Luck and have fun folks.

PM me with any questions about this.

I also want to dedicate this DIY to Andy (Neo328ci) a fanatic taken from us to early in life. I may have not known you, but I always enjoyed your posts.
 
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#6 ·
Well I don't do it for a living anymore. I also bought my stuff wholesale so what I will give is a round about price of what to charge.
Figure about 600 Parts and materials and say 6 hours labor at $100 (what shops charge) in other words about 1200 dollars. Please don't quote me on that because I don't know what a shop will really charge, but that is a give or take.
 
#10 ·
I have to replace my evaporator DIY style and I'm doing the dryer as well (heard this was a must).

Should I do a compressor/condensor flush as well? If so where do you get the parts to do it...or am I better off paying the guy who is recharging the system after i've replaced the parts.

Thanks
 
#11 ·
Protip for Xi guys - the compressor needs to be rotated around a lot to get it out the bottom - it doesn't look like it will but it does come out.
 
#12 ·
My AC went out and I removed the aux fan to see what is going on, the clutch on the compressor looks shot, I can grab and move it easily the entire front is loose. How can I tell if the compressor is still OK? Before it went out I used to get cool air intermittently. This went on over a year actually. I did charge the system myself and then have a shop charge it as well just about a month ago. They checked for leaks and did not see anything. After the shop charged it I was getting a whistle like sound when the AC was on and eventually it gave up completely. I am wondering if over charging would cause this?
Also can the clutch be replaced without taking out the compressor?

Thanks,

Ergin
 
#15 ·
Clutch is a magnetic system so when it has no power the part that holds the belt spins freely. to check the compressor you have to spin the front center part.

A clutch can be replaced without replacing the compressor, but it requires a special puller tool that you can buy from snap-on type of companies.
 
#13 ·
^ I'm interested to hear answers to some of the above as well. My compressor has been making knocking sounds for the past year or two, and it finally seized up the other day. I'm trying to find out what exactly I have to do to fix it.
 
#14 ·
What the compressor did is locked up and it did it so hard it shut my car off. I turned off the A/C switch and kept on driving until I could buy a new (reman) compressor.
This exact same thing happened to my wife on a trip 150 miles away. She was on the highway, heard a clunk and then a bunch of squealing and smoking under the hood. Luckily, she was able to pull over. I had no idea what to tell her so we had it towed back home for about $200 (I was afraid the motor had blown!). If I had known it was the AC, we could have turned it off or cut the belt and driven it home!

Shop charged me $1400 to replace it and when he showed me the old compressor the piston had blown through the case!.
FYI, the system has been trouble free for many years now, so I know he did a good job.
 
#16 ·
hello, when i turn the a/c switch on inside the car i can hear the a/c compressor starts and its blowing a little harder but no cold air is coming out, i just had it to auto-shop to get it filled with freon , but still no cold air, when the car is on, i can turn the a/c compressor clutch around, it looks dead, do you think the a/c is not working because of that...
sorry for my english, am from Denmark

Thanks for any replay or help, Karakanm
 
#17 ·
Just replaced my compressor last night. I found the biggest PITA part of the job was to free up the allen bolts connecting the hoses to the compressor. I had to disconnect one of them from the condenser and the other from the firewall (took out the cabin filter housing then unbolted the clip which holds the port). Once I had those disconnected, fished the lines so it could be moved around a bit and took out the fan. I barely had enough room to pull the compressor out from the bottom.

I want to replace the condenser in a couple days but that requires I drain the coolant from the radiator so I have room to work (according to Bentley I have to remove the radiator). If anybody else has an idea of a way to replace the condenser without have to remove the coolant so I can pull out the radiator to gain access to the condenser, please let me know. :)
 
#18 ·
I want to replace the condenser in a couple days but that requires I drain the coolant from the radiator so I have room to work (according to Bentley I have to remove the radiator). If anybody else has an idea of a way to replace the condenser without have to remove the coolant so I can pull out the radiator to gain access to the condenser, please let me know. :)
I didn't know you have to drain the coolant to replace the condenser. I am planning to work on my AC this weekend. Do you really have to remove the radiator, to have room to replace the condenser?
 
#19 ·
The drier is required if you're replacing the compressor?

My issue is different. I did an engine swap and the crank pulley from the new motor(2006) has 4 ribs while the compressor has 5 (2001).
If there a way that I can just remove the pulley? Would a new drier be needed?
 
#20 ·
Hi folks,
I just got my compressor and drier replaced. The old compressor had the clutch busted. It blew cold air for a bit but shortly after it stopped. Compressor just does not kick in at all anymore. I had the mechanic check the pressure to make sure it is not too high or low. He checked and said everything seems in order but the compressor is not getting the signal to turn on. Even with the original compressor before it went out I used to get erratic on/off and thought it was the clutch giving out but it appears that there is something else wrong. I did some research on the older posts and people mention the outside air temp sensor, my car does not have a display showing outside temp so I am not sure I have this. (first year e46 99 323i). Another suggestion that comes up is the final stage resistor but the symptoms there seems to be different vents blowing mix of cold and hot and I am not sure by symptom matches this. Any suggestion as to what else I should check is appreciated.

Erhan
 
#21 ·
Great right up!!!!! :bow:

It worked like a charm, but I have some minor details to save you some time and frustration.

When you are ready to remove the AC hoses from the compressor, remove the AC left hand side 6mm Allen key bolt to the compressor first. Then you can move that AC hose out of the way and tackle the other 6mm bolt without any interference.

Also the trigger wire to the compressor just pulls out! I was trying to turn it out believing it had a thread! :banghead:

:thumbsup:
 
#27 ·
You do not need to replace the compressor. You would replace the compressor only when it is bad.

The drier is replaced anyting the system is open to outside atmosphere. If you remove and replace any part of your system, then you should replace the drier. It is a dessicant and absorbs moisture.

If you:
replace the evaporator, replace the drier
replace the condenser, replace the drier
replace the compressor, replace the drier
replace the hoses, replace the drier

If you:
just charge and recharge R134a, then no drier replacement.


Always pull a vacuum on the system before recharging a system that you have change parts on.
 
#28 ·
Uhm... Can I / Need I / How to flush system if I don't replace the compressor? If I replace a dryer and expansion valve only, for example? I don't feel good to flush it with a compressor connected; probably I'd need to disconnect pipes from the compressor anyway, right?
Where to get that flush tool, does it require air compressor?
 
#30 ·
This is a really helpful DIY. But I am confused on how to flush the system. Most bottles of a/c flush, and most sites I've read, recommend that the expansion valve NOT be flushed. I assume this is because particulates loosened in the flush might jam in the small orifice of the expansion valve. On our cars, I thought the expansion valve was connected to the evaporator deep in the dash. If so, how do you flush the evaporator without also potentially gumming up the expansion valve?
 
#31 · (Edited)
The expansion valve is NOT buried deep in the dash. It is accessible from within the engine compartment. Take out you fresh air filter right above the engine and on the firewall. If you remove the expansion valve, you can flush the evaporator. Then you can also clean the expansion valve, since it is out and the particles in it can be sprayed.

You need a small torx bit for the expansion valve.
 
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