Replacing AC compressor on 2007 M45

[Sstupid]

My AC compressor has begun leaking around the shaft seal, so I will begin replacement of it and the drier, later this week. I will take some pics but likely won't do a write-up as I already did one on replacing the electromagnetic coil for the AC clutch. Removal of the compressor won't be much different than the stuff in that procedure and you can look up compressor replacements on YouTube. I just wanted to see if anyone has any specific questions about this job. If you do, let me know, and I'll be sure to address them.

[EdBwoy]

Do you have the equipment to evacuate and refill the system or are you planning to take it to a shop for that?
I assume the initial drain depends on the DIYer's level of comfort & creativity

Also, are you using a new OEM unit or used, or aftermarket? Share part numbers in case we need to.

[steve_c]

Do you have the equipment to evacuate and refill the system or are you planning to take it to a shop for that?
I assume the initial drain depends on the DIYer's level of comfort & creativity

Also, are you using a new OEM unit or used, or aftermarket? Share part numbers in case we need to.

I was thinking along the same lines.
Since the system will be open to atmos during repairs, are you going to pull system into deep vacuum after close up and before adding in new freon?
What are you using to measure freon amount you put into the system?
What about refrigerant oil, are you adding any to make up for the loss of oil from the seal leak & residual oil trapped in dryer assembly?

[Sstupid]

The shaft seal or something related to the innards of my compressor went out, leaking out all of my friends, so I won't need to evacuate the system. I do have access to an Inficon recovery unit, but it won't be needed.

1. Yes, the system will be pumped down to vacuum (around -13psi) for an hour. I have the venerable Pittsburg vac pump from Harbor freight (on sale for $68) bought years ago or an old Civic I had.
2. I will be using the recommended amount of Freon in ounces listed on the hood. For the in-between amount of Freon used from a full bottle, I have a small scale. I can take a pic of it when I do the job. It is a cooking scale, I believe. Very cheap from Walmart.
3. For refrigerant oil, I will be dumping the old oil from the old compressor and measuring it. I will then add that amount to the remanufactured compressor. If the reman unit has oil already in it, I will dump it and subtract as needed.
4. I will be using a remanufactured compressor from Rock Auto for $426, and a drier from AutoZone for $18. I wanted a new compressor but they are around $800 and my car has 214k miles, so I went with the reman.

Sorry I didn't get to this, this past week, but the original place I ordered a new compressor from sent me the compressor for a Y34. I was wondering why a new part was so cheap. Waste of a week. Oh well.

[EdBwoy]

... the original place I ordered a new compressor from sent me the compressor for a Y34. I was wondering why a new part was so cheap. Waste of a week. Oh well.

How cheap are we talking about this part?
Last time I was under the Y34 I noticed some green around my compressor, and I think this job is in my near future. The system still works and the A/C feels cold, but I have been toying with the idea of selling the car and I'd like to get that sorted out beforehand.

It's pretty cool that you have all the tools on hand , for my refilling I plan to pay for a shop to do.

[Sstupid]

Brand new Y34 compressors are only $375 because they share a compressor with the Maxima. Cheap compared to a new compressor for my car. If it is blowing cold, don't mess with it.

[EdBwoy]

You're the compressor man, I'll leave it for now.

Btw, did you consider rebuilding the compressor?
If it's just a leak instead of a locked up one, I figured those would be salvageable. As usual, cheap parts but considerable amount of time input for a first timer.
What is your opinion on that?

I have, I believe 2, compressors in my garage and wanted to play with them if I ever got the chance. I can't recall if both of them are for the Y50 or if one is for the Y34. I'll confirm when I can dig it up.

[Sstupid]

Rebuilding compressors is definitely something I leave up to the reman companies. They are usually multiple little pistons pushed up and down by a plate inside that is thicker on one side than the other. That plate, the piston bores, and the main shaft seal are the usual suspects on failures. I think the main bearing went out on mine and took out the main seal. If I have metal in the system, this is going to be a whole different animal. If that is the case, I might scrap the car.

[Sstupid]

Ok, I have some pictures. So, I did detach the connector from the metal bracket on top of the compressor. You just have to pry it off with a small screwdriver and with your hand. It is just slid on to the metal tab and held in place by a dimple on the tab to keep that connector in place. Once you have slid it off the holder, you can move it out toward the radiator, to work with. If any ty-raps are holding anything, just cut them.

This is the tab, on top of the compressor, that the connector is clipped to:


This is what the back of the connector looks like, where it snaps on to the bracket


To separate the connector, first get a small screwdriver and pry the tab down, using the other side of the connector as leverage:


I couldn't do this and get a pic, but I pried that button down with the small screwdriver, held it, then used a larger flathead to pry the connector open from the side, like this (I would have been using both screwdrivers though if I could have done all that and taken a pic):

This is what it looks like unplugged:

[Sstupid]

I pulled the electric fan assembly, the drive belt, and the compressor, today, in about 30 minutes, so removal wasn't bad at all, but thanks to the regular remanufactured BS, I had to go source a couple of bolts the fasten the high and low pressure lines to the compressor, since the original compressor had studs that couldn't be removed. Also, the reman unit had the two connectors I needed on it for the clutch acdtivate and the sensor on the bottom the compressor, but they were both broken where they would mount to the metal frame on the compressor, so they have to just be tu-rap'd up somewhere. I REALLY hate remanufacdtured crap.
I sourced some M8, 1.25x30mm for the job, from Lowe's, but I had to take time to go do it, which pissed me off. Luckily, I noticed this little issue before I started installation.
Tomorrow, I hope to pull the bumper cover and replace the drier, then get started on the vac, leak test, and charge.

One thing of note: my original compressor only had about 1/2 ounce of PAG46 in it. It was supposed to have 3OZ in it, so the shaft seal definitely blew. That's why i had lubricant all over the compressor.

The reman compressor comes with 3OZ of PAG46 already in it. You have to tip it over on to the clutch for 3-5 minutes to let the lubrication reach the shaft seal. The M45 system requires 5.3OZ of PAG46, so I will need to add 2.3OZ to the drier or to one of the those suction compartments you can buy to hook to your suction hose on your gauge set. The M45's take 19OZ of R134 and the cans are 12OZ, so I'll take one whole can and another 7OZ from another.

[EdBwoy]

Thanks for documenting the process SS, but the Photobucket pics won't show for most of us...

EDIT:
I've updated your posts with the Tinypic pics

[Sstupid]

Ok, so some other things to note as I finished up the installation portion today.
1. Replacing the drier (accumulator) requires you to remove both of the radiator brackets and pick up the radiator and move it upward and back toward motor. The drier has a bracket with a bolt at the bottom the keeps the lines seated and you can't even see that bolt without moving the radiator. It is buried in the front frame. I went ahead and drained the radiator and removed the bottom hose but I think you can move it far enough without doing that.
2. To get to the radiator bracket bolts, you have to remove a bracket that the grill assembly clips to. Three bolts, no biggie.
3. To replace the drier, you also have to remove the bumper cover. Lots of bolts if you count the underside fender wells, but only 6 bolts if you don't.
4. To remove the bumper cover you have to remove the front section of each of the fender wells. Couple of clips and 5 bolts.

After the whole thing was put back together, I vacuumed it down and did the leak check, which turned out good. Then I went to put Freon in it and my clutch won't engage. It was dark by then so the saga will continue.
So two other things to not:
5. I found out that power to the electromagnetic clutch is supplied through fuse #79.
6. I found out that that fuse is in a fuse box that is buried behind the battery and all its many panels.

I'll keep this thread updated as I learn more.

Cost so far:
1) Four Seasons Reman Compressor, drier, and o-rings as a kit from Rock Auto. $489.
2) bottle of PAG 46 with UV dye from Autozone. $8.99
3) Box of raven nitilemgloves from Autozone. $14.99
4) Two bottles of brake clean. $4.86
5) Two M8X1.25x30mm bolts from Lowes. $3.89
6) Nissan body panel clips from Autozone 2X. $9.00
7) R134 Freon (12OZ) 2X from Autozone. $27.00
8) Bottle of vac pump oil from Autozone. $4.99
9) Pack of two Schroeder valves for low and high side connections from Autozone. $8.99
10) Bottle of 50/50 antifreeze from Autozone. $15.99
Total: $587.7
Quote from Infiniti: $1959.42

[Sstupid]

Well, the job is done. Fuse #79 was indeed blown. Replaced and clutch kicked on. The compressor had 3 oz of PAG46 from the reman company. My old compressor had only 0.5 oz of PAG so I just assumed a lot of the old oil leaked out, so I left the whole 3oz in the compressor. The drier had almost no PAG in it, so I went ahead and added 2oz of PAG46 during the 19oz Freon charge. That means I added 5oz of PAG counting the compressor. After charging with 19oz of Freon, I only got high side pressures around 130psi with it being 95 degrees and very humid. That number should be around 190 degrees, so I'm thinking I added too much PAG. I am still getting center vent temps around 50 degrees so I'll just run it like it is for now and then get it professionally evacuated and recharged.

[steve_c]

Most of the system oil migrates down into the condenser. You probably had the bulk of your remaining oil their, as well as a bit in evap & lines!
High side @ 190 deg.(low)....outlet ducts @ 50 deg.(a bit low) .....what was your low side pressure under under the conditions you mentioned?

[Sstupid]

I meant to say that my high side was around 150 psi but should have been around 190 psi, not degrees. Oops.

My low side with engine just at idle was around 35 psi. As soon as I get some time, I'll check it again. It is much cooler, now, at 85 degrees, here in Austin. I'm getting center vent temps of 40 degrees with this current ambient temp and humidity, so I'm sure my pressures are different. I need to check the cycling, too. I just ran out of time. Steve, do you know if a low high-side pressure is a common symptom of too much lubricant in an auto AC system? If so, I'll go get it all sucked out and professionally charged.

[steve_c]

my high side was around 150 psi but should have been around 190 psi...My low side with engine just at idle was around 35 psi...I'm getting center vent temps of 40 degrees with this current ambient temp and humidity, so I'm sure my pressures are different. I need to check the cycling, too...do you know if a low high-side pressure is a common symptom of too much lubricant in an auto AC system?....

lol!
I was afraid you might ask about your high side readings, honestly, I do not know what xtra oil would do to high side, as I never diagnosed a high oil that way. The below 3 are the things I have experienced in my career with A/C problems due to high oil condition:

A symptom of the most extreme cases of high oil, (again, in my experience) is compressor lugging. You will actually hear it at the compressor, and see it on the low pressure side of the gauge as it would fluctuate very rapidly. Very dangerous, If lugging compressor fails, system will get contaminated!

Not so extreme overfill might show as poor system performance because the excess oil tends to collect in the evap, and the lower pressures in the evap cannot push out the excess oil. This causes an oil coating in the evap that blocks efficient heat exchange from taking place. A symptom would be insufficient cooling as seen at the outlet register temps, (the temps would be too high).

If the oil blocks or restricts the expansion valve, (or what ever method is used) you might see high low side readings, again, all the above based on my experiences.

You are apparently pretty darn competent in your A/C skills. If it were my car, I would:

1). let all sit overnight, do not start car, check static pressure to be sure it matches Temp/pressure correlation for 134a. Do this to be sure no non-condensibles present.

2). Get a good base line on ambient air temp, hook up gauges & start car, a/c on, let car idle for 10 minutes or so to stabilize A/C & collect high & low side readings as well as outlet register temp. Take readings & check if they are in "normal working parameters" for 134a.

Don't forget, once the A/C clutch kicks off, your outlet register temp will go up some.
When you are measuring the he outlet temp degrees, be sure clutch is engaged!

My thought on your problem is that I am not convinced you have a problem...not yet anyway! like you said, you need to take time & recheck those readings & outlet temps.

[Sstupid]

Thanks for the help, Steve! I'll definitely jump on that later this week. I also have do a compressor/drier install on my 1988 civic hatchback pretty soon. That one is a new compressor though and not a reman. All your info will definitely help. This has me thinking I might replace the condenser on the Civic, as well.

[Sstupid]

Got my readings this morning.

Ambient air temp was 80 degrees with 70% humidity.
1). Static readings for Low/High were 110psi/120psi
With car at idle, max AC, fan on 3:
2). Low/high pressures were 30/140, center vent temp of 46 degrees
With car at 2k RPM:
3). Low/High pressures were 35/170, center vent temp at 45 degrees.

Here is the strange part. I don't get any real change in pressures. High is supposed to go up when low is going down. And vice versa, in a cycle. Mine just kind of hover at the same presssures. This makes me think the expansion valve isn't working. I am technically within the operating range of pressures and temps for R134, but those ranges are pretty wide.

[steve_c]

Got my readings this morning.

Ambient air temp was 80 degrees with 70% humidity.
1). Static readings for Low/High were 110psi/120psi
With car at idle, max AC, fan on 3:
2). Low/high pressures were 30/140, center vent temp of 46 degrees
With car at 2k RPM:
3). Low/High pressures were 35/170, center vent temp at 45 degrees.

Here is the strange part. I don't get any real change in pressures. High is supposed to go up when low is going down. And vice versa, in a cycle. Mine just kind of hover at the same presssures. This makes me think the expansion valve isn't working. I am technically within the operating range of pressures and temps for R134, but those ranges are pretty wide.

Question on your static readings'
Did the car sit overnight, and static pressures checked with unstarted car?
To get static temps, you must have even ambient temp throughout the engine compartment, that is to say, the same as the outside air temp of what you recorded, (80 degrees).
Using 134a temp/pressure correlation chart, your static pressure should be about 89 psi (see chart) for both sides of your gauge.
You seem to be recording 20psi higher than you should on low side, and 30 psi higher on high side, when both should be equal (at 80 deg.F ambient), @ 89.xxx psi as read by both gauges.
I am talking about static, car off readings, nothing else....check a few charts, I included one below, am I correct?

http://www.csgnetwork.com/r134apresstempconv.html

[Sstupid]

Oh crap. Those static pressures are with the car still pretty hot. That was only an hour after getting home from work. I'll check them again tomorrow when the car is cold.

[Sstupid]

Ok, my static pressures are 82/82 psi when cold. Ambient is 72 right now. According to your chart I'm about 10 psi high? From what I've read, static pressures aren't an indicator of under- or over-charging. My dynamic pressures make it appear that I'm under-charged, but I know that is not the case. I measured out, by weight, 19 OZ of Freon, but after the initial readings, I went ahead and put the whole two, twelve-ounce cans in and received no perceivable bump in dynamic pressures. I can't be under-charged.

I might just drive it and leave it alone until winter, when I can get it professionally sucked and recharged.

[O5Q45]

Hello guys from the Q45 group- just wanted to ask a quick question- my compressor in my 2005 Q45 is knocking and clacking at idle. Since the M45 and Q45 share the VK45DE would they also share the same a/c set up? Wondering if these costs and symptoms would be likewise on my Q- thanks for any info-

[amc49]

I don't see how you guys get any cooling at 190 psi highside. I haven't done a Nissan yet but the refrigerant needs certain pressures to work and doing mine I always use 300 as the go to number at 100 degree day or so. Sometimes up to 325. Mine won't even begin to get cool until over 225. The high fans on two cars I have don't even come on until 275 psi and per the service manuals.

I used that 190 number when I used to do R-12, that is correct for that refrigerant.

I NEVER charge by amount, there are simply too many variables unless you have refilled oil in to a completely empty flushed clean system. I charge to the correct pressures and life is good, it compensates for too much oil or too little.

[Sstupid]

The high pressures are significantly different for different systems. My Honda is more like 250psi on a 95 ambient day.

[Sstupid]

I got impatient and had my brother recover my Freon with his Inficon recovery machine, then I removed the compressor and dumped out the PAG46. It measured around 4 ounces so I removed 2.5 ounces And reinstalled it, sucked the system down for an hour, and leak-tested it. I refilled with new R134 and found how I screwed up. I now have center vent temp at 40 degrees with 92 degree ambient temp. My pressures are now 38/198 at that same ambient. My statics are 72/74ish.

How did I screw this up you ask? Well, I am an idiot, so I didn't read the stupid Freon cans before I charged the syste. The R134 cans I bought were a brand called Avalanche. The front of the can didn't say anything about having PAG in it, but guess what. When I went to get more Freon, I went back for the same brand and read the back of the can this time. The Avalanche brand I charged with the first time had 1OZ of PAG in each can. So, not only was I an two ounces low on Freon, I was also two ounces too high on the PAG charge. No wonder the darn system wasn't cooling. I effectively filled the evaporator with PAG, making thermal transfer almost impossible. Anyway, lesson learned. Read the can.

[steve_c]

......A symptom of the most extreme cases of high oil, (again, in my experience) is compressor lugging. You will actually hear it at the compressor, and see it on the low pressure side of the gauge as it would fluctuate very rapidly. Very dangerous, If lugging compressor fails, system will get contaminated!

Not so extreme overfill might show as poor system performance because the excess oil tends to collect in the evap, and the lower pressures in the evap cannot push out the excess oil. This causes an oil coating in the evap that blocks efficient heat exchange from taking place. A symptom would be insufficient cooling as seen at the outlet register temps, (the temps would be too high).

If the oil blocks or restricts the expansion valve, (or what ever method is used) you might see high low side readings, again, all the above based on my experiences.......

Wow!
diagnosing compound problems are the most difficult, glad I was able to pitch in with a few thoughts!

[Sstupid]

Thanks, Steve! You da man!