A/C repair help

740iS · #1 07-19-2017, 02:29 PM

Anyone in the SF East Bay (read far East Bay) area who has replaced the A/C compressor on a 4.8i interested in helping do that on mine? I've not played with the A/C that much in a very long time and would appreciate the assist. Picking up a new set of gauges and vacuum pump soon, but have to finish my diagnostic to make sure I'm correct.

A/C blows cold on drivers side only and just cooler than lukewarm on passenger side. As of last night getting a grinding style noise from what appears to be the area of the A/C compressor (passenger side front) that I can only assume is the clutch bearing or compressor itself. I'll be putting her on ramps this weekend after parking her tonight (don't want to grenade the compressor) and make sure it isn't the water pump, power steering pump or alternator.

But the noise doesn't seem to be coming from those points. Noise is present with A/C on or off and goes with the engine speed too. This is what is making me think compressor.

Sorry but don't have a video of the sound (yet) so it's kind of hard to fully explain.

If you have any insight and/or able to schedule a Saturday (probably in a couple of weeks) to assist/direct. I'd be grateful. If you come to assist, I will be happy to provide food and beverage as well.

Thanks in advance

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Nanniepoo · #2 07-19-2017, 03:11 PM

If the air is warmer on one side than the other, it could be the mixing valve. Doesn't explain the grinding though.

740iS · #3 07-19-2017, 03:15 PM

I figured that the flap was the cause of the warmer on one side, but a bit of research here also mentioned possibly needing a recharge too. But if the grinding is the clutch/bearing, then that issue will be moot when the repair and recharge is complete.

ard · #4 07-20-2017, 11:34 AM

The system is designed to be charged based on refrigerant WEIGHT. How do you plan on doing that with gauges???? The specs are rather tight on this....

If your comp has failed and contaminated the system, you will need to flush/clean- otherwise you will kill the new comp in short order.

Last time I had a failed evap (so no contamination) I just changed it and took it to a shop I knwo- he was nice enough to do a pump down/leak test- then recharged to the right amount. Fine since. (This was on a 2001 MDX about 3 years ago)

SeanC · #5 07-20-2017, 11:47 AM

I think this video might help:

https://www.youtube.com/watch?v=5qd0e-vVxQA

740iS · #6 07-20-2017, 12:38 PM

Quote:

Originally Posted by ard

The system is designed to be charged based on refrigerant WEIGHT. How do you plan on doing that with gauges???? The specs are rather tight on this....

If your comp has failed and contaminated the system, you will need to flush/clean- otherwise you will kill the new comp in short order.

The weight is simple actually, you use small cans of freon to get as close to the weight as possible, then just a bit more from another can until the Hi and Low gauges are reading properly.

Compressor actually didn't fail, it is noisy from the clutch/bearing as I was able to confirm yesterday. So no issue with contamination. To keep it from failing at this point until I replace it, I cut off the A/C belt and the engine is silent once again.

Sean, thanks for the video, I'll be sure to take a look.

740iS · #7 07-25-2017, 02:34 PM

Quote:

Originally Posted by SeanC

I think this video might help:

https://www.youtube.com/watch?v=5qd0e-vVxQA

That's a great video and the sound the bearing was making is nearly identical to what mine was doing. Unfortunately, the bearing on mine whether A/C on or off was starting to cause some binding and causing undo strain onto the engine. So I think getting a new compressor was a better choice for me.

Since I still need to drive the car daily, I also had to cut off the A/C belt just in case the internals of the compressor were starting to go. Didn't want it to grenade into the lines and cause any more damage.

Hopefully, I'll be attacking the install this weekend or next.

Would like some opinions though. Since I'll be loading the r135a from scratch, what would people recommend? Should I get a can that also has stop leak in it too or just pure r135a? Any recommendations on brand and/or "pure synthetic"?

Thanks again for that video!

SeanC · #8 07-27-2017, 11:30 AM

I'd just put pure R135a. When I had the same issue on my e46, I just filled it up with a can from Walmart, and kept driving it for another 30,000+ miles before I sold it. It was still blowing ice cold.

If you suspect you have a leak, then use a dye while you're filling it up, and monitor the A/C lines on a regular basis. Then properly fix the leak if there are any. At least, that's what I'd do.

roboe70 · #9 07-27-2017, 08:50 PM

Quote:

Originally Posted by 740iS

Since I still need to drive the car daily, I also had to cut off the A/C belt just in case the internals of the compressor were starting to go. Didn't want it to grenade into the lines and cause any more damage.

What? You aren't daily driving the E38? J/K

I picked up an E70 as well (09 3.0) and it threw the AC belt. Since I am driving the E38 in the warmer months I can take some time to get the compressor checked and likely replaced, before the garage queen goes back to napping in the winter.

Do you have the stretch belt for the AC belt? I bought a tool to remove and replace mine when I get around to addressing the issue.

740iS · #10 07-28-2017, 01:49 PM

Okay, call me stupid, stretch belt? No standard belt, release the tensioner, install belt reapply tensioner. Maybe you need the special tool on the 3.0's but other than having to remove the serpentine belt to install the ac belt, it looks very straight forward if you ask me.

Oh I'm itching to be driving the E38, but just got her front end, rear bumper and roof repainted and doing some meticulous installations of the bumper trim, sunroof opening gasket. Then a retrofit of an electric cooling fan to take off the belt driven fan and US NBT system that includes HD and Sirius. But it's so blasted hot right now (103 to 107) and no breeze that I can't get myself to go out to the garage to work on her.

Plus I have an NBT EVO upgrade to perform onto the E70, but same problem with the heat and unfortunately between my E38 and an E36 ti in the garage that I am restoring for one of my boys, I don't have the room in there to work on the E70.

Doing this A/C work is bad enough. LOL

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