AC compressor packed up at 170k+

[andrewwynn]

I've been trying to find this video for a long time and just realized i can search by type and is slow motion.

https://share.icloud.com/photos/01ap...WyAQS3uoFuKhQg

Listen how realistic at 1/8 speed!

[TriX5]

Finally got around to this, to my surprise this can actually be done completely from the top. The key for me was removing the fan and shroud, then the compressor can be taken out forward and turning toward the middle of the engine bay. I did not drain the coolant or remove the lower radiator hose. Much simpler than I was anticipating but plenty fiddly to remove and install the compressor bolts. Remember folks, this is what I did, not saying you should :-). A few pics below.

I purchased a used Denso compressor, same spec as my original. Furthermore:
Two cans of AC pro AC flush & cleaner
All 7 O-rings. RealOEM part # were correct for my application, '03 4.4 V8.
New desiccant tube.
Bottle of PAG46 AC oil (the specified oil for the Denso compressor).
A 6mm hex key cut short to get to lower pipe on the compressor.
One 12mm bolt to pull the desiccant tube, used an old suspension bolt about 80mm long.
Compressed air and a shop vac certainly helped.
You also need R134a, one can (340grams) and a bit as well as a vacuum pump to fill the system once the compressor is installed.

Took off the splash shield from under the car, not strictly necessary but it helps removing the AC belt tensioner and routing the main belt (I had previously removed the AC belt when the failure first occured). Also removed the frame stiffener plate to get at the rear bolt but after the fact I can attest that the rear bolt is easier to get to from the top if your hands fit back there. The rear bolt can be seen from above and I used a short flat 12/13mm wrench though a regular wrench might fit.

I got the rear bolt out from below, the bottom bolt from below, poking in from the wheel well with a long extension. The top bolt can be seen once you get the air box and secondary air pipe out of the way. The two AC lines attached to the compressor can be easily removed once all three bolts are out. Some of the wiring living there is best moved out of the way as well. I removed all four AC lines from the car and flushed them collecting the flush liquid, nothing much of note came out of the lines making me less worried about the compressor failure. Installed the new O-rings using a bit of the PAG46 oil before installing the lines.

Then the desiccant tube removal was next. The brackets holding the radiator have to be removed and the radiator pack can be tilted back just enough to get access to the desiccant tube. A pressure warning sticker hides the torx cap above the desiccant tube. A clip needs to be removed and then a 12mm bolt can be used to pull the desiccant tube. It resisted my best attempts at removal quite a bit...... When I got it out, the bottom 40mm had split leaving that piece behind as well as the desiccant balls. A piece of 3/4" pipe and the shop vac fortunately got these pieces out after a few attempts. At that point I ran the flush through the condenser in a number of cycles alternating top and bottom port on the passenger side, each time following up the flush with compressed air while vacuuming the pipe on the driver's side simultaneously. After repeating this process about five times I did not see any more debris or dirt coming out when applying compressed air to the AC line connections. I assumed this process removes all the AC oil from the condenser as well. I drained the oil from the compressor to reset the count.

Reinstalled the compressor leaving the AC lines off at first, then cut the hex key short to allow tightening the lower AC line. Very little space between the bolt and the frame rail there. It might be possible to put the lower AC line on before installing the compressor but that leaves too many pieces to be juggled all at once IMO. (The top and rear bolts have to in the compressor before moving it in to position and they have a tendency to fall out....) After a few minutes of choice terminology I got everything lined up and got the top bolt hand tight. Next the rear bolt has to be turned enough to be hand tight as well. I was able to put the bottom bolt working from the top and once everything was in place snugged it all up. A second pair of hands might have helped at this stage but it can be done by one person as well.

I added the required oil to the compressor, drew a vacuum which thankfully held, then started the car with AC at full tilt. When the first can was mostly in, the compressor had engaged already and cool air started to appear. Obviously a new compressor would have been the preferred route but this option saved me some money and allowed me to understand the complexities of this repair before putting expensive parts to the test. I realize that I might not get 175k miles out of this compressor but if I need to do it again it will be much quicker and worry me less.


The pics: 1. Here is the compressor on its way back in, 2. The wrench on the rear bolt, tight but doable from above, 3. A view on lower bolt from under car, an extension can get to it from below frame rail.

[X5chemist]

Nice work. Wow the transmission oil cooler is on the same side? 3.0i have them on the opposite side.

Did you install a new pressure switch? Mine failed causing the aux not to turn on. Eventually, engine cooling turned it on. Once the fan was on, A/C cooling was no issue. After installing a new switch, the AUX fan kicks on almost immediately. It's nice to have A/C down to <42F

[Henn28]

Originally Posted by X5chemist

Nice work. Wow the transmission oil cooler is on the same side? 3.0i have them on the opposite side.

Did you install a new pressure switch? Mine failed causing the aux not to turn on. Eventually, engine cooling turned it on. Once the fan was on, A/C cooling was no issue. After installing a new switch, the AUX fan kicks on almost immediately. It's nice to have A/C down to <42F

Agreed, and thanks for the great write up. I’m at 175k on mine and assume this job is in the not too distant future. Compressors routinely show up on clearance on FCP and I’ve been thinking of grabbing one.

Where is the dryer in the system?

[X5chemist]

The drier is on the condenser left side. Go here to the 6:00 mark.. The cover cap needs to come off first. Screw in a proper size bolt into the drier. Use a long lever and pry up on bolt.

[TriX5]

Originally Posted by X5chemist

Nice work. Wow the transmission oil cooler is on the same side? 3.0i have them on the opposite side.

Did you install a new pressure switch? Mine failed causing the aux not to turn on. Eventually, engine cooling turned it on. Once the fan was on, A/C cooling was no issue. After installing a new switch, the AUX fan kicks on almost immediately. It's nice to have A/C down to <42F

Good point, I will get one and install it when I get back home. (Right now I’m on the road for a few weeks and the E53 is taking a break ). The day after I finished the repair the aux fan didn’t come on until I started to check the pressures again and restarted the engine a few times. I have not got a full charge yet either, passenger side is nos as cold as driver. Overall I’m pleased with that I could get this far being very new to working on the AC system.