Odd sound from AC compressor - PeachParts Mercedes-Benz Forum

TheDon · #1 04-08-2014, 09:35 PM

http://youtu.be/evZTc_Ubbsk

W123 300D

Excuse the video. I recorded it landscape but YouTube uploaded it in portrait. But just listen. There is a almost like banging sound and metallic whining is how I describe it.

AC stopped working a few days ago I think or longer. Fiancé just mentioned it yesterday. Any ideas what could be wrong? I installed a brand new, expensive, behr compressor after completely flushing the system with some awesome dance causing fluid. New seals everywhere and a new hard line in front of the valve cover and expansion valve, etc etc.

ROLLGUY · #2 04-08-2014, 11:09 PM

Quote:

Originally Posted by TheDon

Odd sound from w123 AC compressor - YouTube

W123 300D

Excuse the video. I recorded it landscape but YouTube uploaded it in portrait. But just listen. There is a almost like banging sound and metallic whining is how I describe it.

AC stopped working a few days ago I think or longer. Fiancé just mentioned it yesterday. Any ideas what could be wrong? I installed a brand new, expensive, behr compressor after completely flushing the system with some awesome dance causing fluid. New seals everywhere and a new hard line in front of the valve cover and expansion valve, etc etc.

Listening to the sound, it sounds like you need a Sanden upgrade to me

BenzTurbo · #3 04-09-2014, 05:24 AM

Quote:

Originally Posted by ROLLGUY

Listening to the sound, it sounds like you need a Sanden upgrade to me

I agree!

my R4 is getting louder every day. At idle I hear a "crunch" sound every couple seconds like it's grinding up rocks. It's was only 75° outside and it gets worse when it's hotter. Huge v8 clutch fan and aux fan so head pressure is fine in this weather but those compressors are just turds. The whole front of the clutch fell off on my dad's 300d a year ago. Just pathetic... I got my "enhanced" sd7 ready to go

TheDon · #4 04-09-2014, 07:59 AM

It's brand new. I spent $400 I think on the darn thing. Also this was with the HVAC unit set to off.

ROLLGUY · #5 04-09-2014, 10:48 AM

Quote:

Originally Posted by TheDon

It's brand new. I spent $400 I think on the darn thing. Also this was with the HVAC unit set to off.

The entire Sanden upgrade thing started with a similar thing happening to me. I got a new Compressorworks R4 (supposedly the only manufacturer nowadays), and it was bad right out of the box. I returned it and got another one from another source (the first place only had one, and I did not want to wait for another one), and installed it. It was bad as well. I was fortunate to get my money back on both, but the cost and effort to install and charge the system was lost. I decided to fabricate a bracket to use a Sanden compressor. The rest is history. I will not even suggest to my enemy to run an R4 in their 'Benz....Rich

TheDon · #6 04-09-2014, 02:33 PM

Still selling the brackets and stuff to convert the w123? If this compressor has died then I probably should.

I'm just curious as to why it's making noise even when the clutch isn't engaged. I put the proper amount of oil in the system too.

compu_85 · #7 04-09-2014, 03:19 PM

If it's making noise when the clutch is open either the clutch gap is wrong or the bearing is bad. I couldn't tell from the video... when the clutch pulls in does the noise stop?

-J

ROLLGUY · #8 04-09-2014, 04:56 PM

Quote:

Originally Posted by TheDon

Still selling the brackets and stuff to convert the w123? If this compressor has died then I probably should.

I'm just curious as to why it's making noise even when the clutch isn't engaged. I put the proper amount of oil in the system too.

Agreed about the clutch gap, and yes I am running a Spring Special: 7 cyl compressor for the price of a 5 ($20 upgrade for the 7).

TheDon · #9 04-10-2014, 02:26 PM

Clutch doesn't pull in period. I have the evap sensor bypassed. What's the other sensor I can jump go get it to engage?

BillGrissom · #10 04-10-2014, 03:45 PM

It is simple to bypass the AC clutch relay. Unless you have a 1985 300D (please, always tell us, it often matters), the relay is under the black plastic cover on the driver's inner fender. It is the fwd relay. Pull it out and jumper a 12 awg wire from the 30 to 87 pins in the connector (same pins as a U.S. 30A relay). The clutch should engage. If not, get a little dirtier and pull the connector off the clutch and connect two wires with spade lugs, run one to BATT+ and other to GND. I don't think it matters which polarity. Clutch should definitely engage then. If not, measure the resistance of the clutch.

I wouldn't give up on your new R4 yet. Probably worse-case is that the clutch bearing is bad, but that would be more of a squeal. I think you can change the bearing cheap and easy if you have a shop press. You can buy a new clutch, but not cheap unless on ebay. I agree it sounds more like the gap setup on the clutch. After using it a bit and it wears, it might quieten down. I never set the gap. You shouldn't have trouble after paying $400, but removing it is a b***ch so try to tweak in-place. I bought a new R4 for $70 recently on ebay. I converted my 1985 to a Sanden w/ RollGuy's bracket, but have enough R4's to keep the 1984 going on that for years. I converted my R4 to PAO oil w/ Duracool refrigerant recently. That new oil is supposed to stay put in the compressor better, so should help. Can't say how it cools since currently I get cold tubes and evaporator, but no cold air in the cabin (even w/ heater core bypassed), so must dig into the climate door controls.

ROLLGUY · #11 04-10-2014, 05:03 PM

Keeping oil in an R4 is the biggest challenge, and that is the major reason for their early demise. The Sanden has a separate oil sump, so keeping them lubricated is much easier. A Sanden will last so much longer than even the best R4 for that reason alone.

TheDon · #12 04-10-2014, 05:29 PM

Gap setup on the clutch? I don't recall having to do anything related to the clutch when I installed it.

ROLLGUY · #13 04-10-2014, 07:05 PM

Quote:

Originally Posted by TheDon

Gap setup on the clutch? I don't recall having to do anything related to the clutch when I installed it.

You should not have had to do anything to it unless it was damaged in shipping, or not tested before leaving the factory. Maybe something just came loose. A close up video would help figure out what might be the problem.

TheDon · #14 04-11-2014, 06:00 PM

Close up of the clutch?ill try my best.

TheDon · #15 04-16-2014, 10:23 AM

Parts place I got my R4 from says it has a 1 year warranty. So I'm thinking about just taking the current compressor and swapping them out. I just have to evac and charge the system.

Or buy the conversion kit and sell the new compressor I get to recoup some cost