Confirming steps to replace A/C compressor

[john steele]

Hi all - regarding a 2000 3.8L w/ 75K miles.

Short history: A/C stopped blowing cold several summers ago. Recently took to a shop & they diagnosed the entire system is solid (no leaks), except at the compressor. Upon hearing the $1000 pricetag to replace the compressor, I came to this forum and I've appreciated all the info.

#1 Question regarding new O-rings
Can I lubricate with PAG oil, or must I find "Mineral base 525 refrigerant oil?"

The following is what I've learned from multiple-dozens of posts.

1. Since I'm replacing the compressor, I'm also replacing the accumulator.
2. Remove old compressor, drain oil & measure. If less than 2oz , then add 2oz to new compressor. If more than 2oz, add that amount.
3. Install new compressor with new PAG oil.
4. Remove old accumulator, drill hole at bottom to drain oil & measure. Add 1oz more than was drained.
5. Install new accumulator.
6. Vacuum system (rent from Autozone or buy from Harbor Freight).
7. Charge system with a Recharge Kit that includes a pressure gauge.

Am I missing anything? I know the O-rings are critical, but I've read that you could use mineral oil from a drug store. Is this correct, or will PAG oil work?

My DIY skills are above average. I just want to do this right the first time.

Thank You! :bowdown:

[Rob Bell]

Re: Confirming steps to replace A/C compressor

I would use the PAG oil on the O-rings since it's designed for AC systems.

[spydercam]

Re: Confirming steps to replace A/C compressor

For what it's worth I used the PAG oil on my MR2's o-rings and so far so good 2 years later. Good luck and post up more info when you do this. I am most likely going to have to do it myself soon. BTW where did you pick up your compressor from, how much?

[cam98aro]

Re: Confirming steps to replace A/C compressor

our compressors take PAG 46 iso oil

[ssms5411]

Re: Confirming steps to replace A/C compressor

The recharge kit comes with 2oz. of oil in each can, at least mine did with stop leak and the gauge, so I would just do the compressor with oil and when you go to do the freon just half way through filling it turn the can upside down so you get the oil going into the accumulator. Mine took just about 2 of the 12oz. cans. There is also a reducer valve up towards on the line where the PCM is, it is almost like a little filter and reduces pressure, I forgot to do mine but it is running fine. Yours is newer so you should be fine. I had to call my friend Bobby who works at a dealer to make sure the oil in the cans were good for the A/C, he said it was fine and any kind of lubercaint on the O-rings is fine like silicone spray or even reg. motor oil to keep then from not getting dry. I always call him since he did my rebuild on my motor 7 years ago and tranny replacements and rear end replacements. Smart guy about 20 years with GM, races his 1500HP dirt race car here and Nevada. Also make sure it is dry out and turn your A/C to max when refilling and you might get away with not having to vacuum the system. I got away with it in 100 degree temp 5% humid out. Good luck

[john steele]

Re: Confirming steps to replace A/C compressor

Thanks for all the replies, the job is done perfectly & the A/C blew cold for a 105+ temp trip to Las Vegas from Ventura, CA.

After talking with smarter DIYers, I cheated and got expert help.
A buddy's 70-year old Dad is a retired shop owner who works out of his garage because it's less boring than watching TV.
I got a world of experience.

1. Haven't seen it posted before, but Replace the Orifice Tube along with the Compressor and the Accumulator. The Orifice Tube cost less than $4 and is a tiny inline screen that is very easy to get at. Mine had two tiny shards of metal, which meant we should flush the system to assure all metal shards were out.

2. Regarding PAG oil. I finally found in my original GM Service Manual that the correct oil is PAG 100. Looking further on the internet, found some stuff about the original GM Part number 12345923 was for PAG 100 until around 2004. Then for some reason the P/N changed to PAG 46 and it has created confusion at dealers when asked why. So PAG 100 is the best viscosity.

3. Regarding lubricating O-rings. GM P/N 12301108 (525 viscosity mineral base refrigerant oil) is the best to use, is easy to get at any GM dealer, and my mechanic savior had some in his garage.

4. It really was simple to get at the compressor, 5 bolts and it was out. Put 2oz of PAG 100 in the new compressor and bolted back up. The Accumulator was also a cinch.

5. It held a full vacuum, took a sweet charge, and blows cold. I was really glad to have flushed the system after seeing the Orifice Tube. Plus my buddy's Dad has literally done hundreds & hundreds of A/C jobs.

Can't beat good advice. This site is the best ever for a V6 owner. Thanks all!

:burn:

[DiskMan]

Re: Confirming steps to replace A/C compressor

4. It really was simple to get at the compressor, 5 bolts and it was out. Put 2oz of PAG 100 in the new compressor and bolted back up. The Accumulator was also a cinch.

Now that's the problem that I'm having, removing the 5 bolts. The front 3 came out with little fuss but the 2 in the rear I can barely reach. I've read, but I wonder about how correct it is, you can take out the front 3 bolts, pull the compressor forward and remove the back bolt holding the lines in place? He never mentioned the 4th bolt holding the compressor in.

I was sporting a 1997 Camaro V6 3800 Series II...

[mtscorvette]

Re: Confirming steps to replace A/C compressor

i've never tried that. it might work but they way i've gotten good at doing it (did it a bunch of times lol) is take a long extension with a universal on the end and go at it like that. i think i went in like behind the motor mount. kinda where the motor and tranny meet. its not too bad like that as soon as you get it on the bolt. good luck