A/C compressor clutch makes noise

[shogun]

when I start a/c the clutch engages and the sound is like a bad bearing(?), still works fine, sometimes no noise, sometimes noise. A/C off: sound is gone. Today we checked and it is definitely the a/c compressor clutch (bearing?)
According to the parts catalog I have
Magnetic clutch 64 52 8 350 058
Only in conjunction with Ribbed v-belt 11 28 1 736 999
Tropical version


Application OEM Numbers Competitive Cross Reference

CO 22025 CL 1769
Dia. 124.8mm, 4.91"
Grooves 5 & 3
Mount 20.8mm, .82"
BMW
91 525i 2.5L
94-91 750i & 750ils V12 5.0L
92-91 850i V12 5.0L
94-91 850ci V12 5.0L
95-94 850csi V12 5.6L

According to my google search that would be for example
CL 1769
http://www.polarbearinc.com/pbpc/hom...l#Anchor-14806

Questions:

1
Can the a/c clutch be changed on the 750 without removing the compressor in the engine room? Any need to recharge gas later or no need to touch the charged system? From the parts catalog it looks like it is separate, but maybe someone has done it already and can give some practical hints.

2
Any source other than the one I just found above for a a/c compressor clutch? Links? Repairs?
Should be a 10PA17C Compressor installed.(?)

Thanks for any comment

[Prospeeder]

The clutch bearing is somthing you can replace without breaching the system yes. Im sure if you removed the fan shrowd or maybe even the radiator you would have plenty of room the repair it on the car. There are some special tools required to pull off the clutch assembly tho

[shogun]

thanks, I found this compressor clutch hub remover & installer kit
http://centuryautoair.com/mcart/index.cgi?code=3&cat=17

just trying to gather some info at the moment. But if such kit costs around $100 or more, then maybe better I buy a recon one? We'll see. Maybe someone has a link to a repair site, so we get a more clear pic what is needed/to be done.

more for the collection
http://www.densoklima.de/schaft.htm
simple tool use
http://foto.arcor-online.net/palb/al...3766393264.jpg
http://foto.arcor-online.net/palb/al...3966333462.jpg
http://foto.arcor-online.net/palb/al...6537643761.jpg
shaft seal
http://foto.arcor-online.net/palb/al...3133363839.jpg

the old R12 compressor for the 750 has on the underside a lock sensor
http://foto.arcor-online.net/palb/al...3065343564.jpg
photo repair story
http://wp1016621.wp027.webpack.hoste...689/f00689.htm

http://forums.acuralegend.org/rebuil...o-c-t122.html?

[shogun]

question, if there is an compressor expert or someone who has repaired it before:

when aircon is off, there is no noise, when aircon on and the magnetic clutch has engaged, the metallic noise starts. But not always. And it is not like a bad beraing, it is a kind of higher pitch metallic sound like two metallic parts touch each other while rotating, no very loud and only really noticeable when hood is open.

So is it the magnetic clutch?
Or could it be the bearing of the compressor?
My understand is that the compressor is only rotating when the magnetic clutch is engaged? Wrong or right?
I have an old compressor from a parts car, but that is stored since 3 years. So the magnetic clutch I could use, but I am afraid that the seals of the old compressor are dried up and I would have to reseal it first.
Easiest would be the magnetic clutch.
If so, I will try to change next weekend, if there is no snow like past weekend, still quite cold here.

Just found a similar prob on the M3 forum, same compressor, he solved it with WD-40 onto the shaft
http://forums.bimmerforums.com/forum...=860105&page=2


edit: here all the details with bearing number and where to order:

step 1 remove the 10mm bolt
http://i4.photobucket.com/albums/y14...DSC00654-1.jpg
Then you pull the clutch end off.
http://i4.photobucket.com/albums/y14...DSC00655-1.jpg
That's a crappy pic of the end of the clutch and the 10mm nut + washer
http://i4.photobucket.com/albums/y14...DSC00656-1.jpg
Look with a mirror you will see a snap ring.
http://i4.photobucket.com/albums/y14...DSC00658-1.jpg
With snap ring pliers you can remove it but this takes patience
http://i4.photobucket.com/albums/y14...DSC00659-1.jpg
Now it's removed you can see the bearing.
http://i4.photobucket.com/albums/y14...DSC00660-1.jpg
With a socket you can drive the old bearing out.
The little lip ring will become loose. Do not lose it and take note of how it goes in.
http://i4.photobucket.com/albums/y14...y/DSC00684.jpg
then you can insert the new one using the old one to drive it in.
Dont forget to isert the lip ring first and in the correct way
As you are driving the bering in, get the pulley on a surface that allows the lip ring to stick out as you tap it in all the way. If you do it on a flat surface, you will damage the lip ring.
http://i4.photobucket.com/albums/y14...y/DSC00686.jpg
http://i4.photobucket.com/albums/y14...y/DSC00688.jpg
http://i4.photobucket.com/albums/y14...y/DSC00687.jpg
BTW the OEM bearing is a NACHI Part Number 30BGS10DST2 (also says 190 on it)
The replacement C&S bearing says 30BG05S2G-2DS

reinstalled the clutch as it was and the pulley would not spin freely as it should. Basicaly the clutch was engaged at all times. I suspect there is a small difference in the width of the bearing when compare to the original. But I found an easy fix. Use the washer you see in the 3rd pictures and insert it INSIDE the splined shaft of the end of the clutch. It will make the piece come out just enough to give you the clearance you need for the pulley to spind freely. (sorry no pics)
The clutch bearing spins when the AC is off, engine running (clutch disengaged). When the clutch engages, the pulley & compressor shaft turn as one. If your noise is only with AC running, suspect the compressor is damaged.


A/C clutch bearing DIY

--------------------------------------------------------------------------------

Again, make sure it's the bearing.

Quick DIY for six-cylinders:

Jack the front of the car up, remove the splash panel.
Remove the A/C belt by releasing the tension on the A/C tensioner.
At this point, if you rotate the A/C pulley, it will or will not feel smooth; same for the tensioner pulley.
If it's the A/C, the A/C compressor is held to its mount by removing its four bolts. This will give it enough play to move about an inch in any direction.
The pulley is held on by a 10mm head bolt, remove the cover, then an external snap ring about 1 1/4" - this is the hard part, getting the snap ring pliers at the right angle to release that circlip.
Once the circlip is removed, the pulley (with bearing) will come off the shaft. Watch out for two shims between the pulley and the shaft to space it away from the clutch slightly.
The old bearing can be pressed or pounded out with a 36mm (I think) socket, the new one pressed in with a vice or press the same way - make sure the new one is completely seated.

Re-assemble in reverse order.

I got my bearing from ESI (bearingsdirect.com), P/N 30BG05S2G-2DS - the bearing is a double row radial, 30mm ID, 52mm OD, 22mm wide.

[shogun]

tried yesterday. The pulley is wobbling terrible when AC is on
Got the clutch end off like this
http://i4.photobucket.com/albums/y14...DSC00655-1.jpg
the clutch liner is at or below the limit. There were 3 tiny shims installed, these are to make the correct distance/clearance, kind of spacer adjustment. Took off 2 of them, they are very thin, we are talking here of washers below 1 mm thickness.

Here it says:

Measure and adjust A/C clutch air gap by adding or removing A/C clutch spacers. The gap width specifications should be included with the new clutch assembly.

Read more: How to Replace a Compressor and Clutch | eHow.com http://www.ehow.com/how_2122053_repl...#ixzz1ESglYxy0

AC works, less wobble, but still some noise. But due to limited space I could not install a standard jaw puller to get the pulley of and I did not want to destroy something as car is needed next day. Appears I need a special puller

Anyone knows where to get this clutch remover and clutch installer from a seller which ships overseas, or has one to lend? Looks like the number is
54 1319
15 7459 (?)
http://www.bernardembden.com/xjs/comclutch/index.htm

I should have read this before starting

Photographed below are the clutch installer (in hand) and clutch puller. You will need both these tools.

Don't even think about starting this project without them.

found this info also for reference:
Removal of Hub/Armature
Assembly (9)
Special tools must be used to avoid damaging the compressor.
A. Remove shaft nut (11) with a 13mm socket wrench and spanner wrench.
B. Remove lock washer (10).
C. Remove hub/armature (9) with a hub/armature removal tool (reference Chrysler Tool # C-4561 or equivalent).
D. Remove shims (8) from the hub/armature and shaft.
Step 3A: Removal of Rotor/Pulley Assembly
(4) (All compressors except HR980)
A. Remove rotor/pulley snap ring (5).
B. Slide rotor/pulley assembly (4) off the compressor (1) nose. If rotor/pulley assembly is hot and will not slide, DO NOT FORCE! Allow the clutch to cool and then proceed.
C. Proceed to Step 4.
Step 3B: Removal of Rotor/Pulley
Assembly (4) and Field Coil Assembly (2)
(HR980 Compressor only)
A. Disconnect the electrical connection on the field coil (2).
B. Unscrew the rotor/pulley retainer nut (6) with a spanner wrench.
C. Slide the rotor/pulley assembly (4) off the compressor (1) nose. If rotor/pulley assembly is hot and will not slide, DO NOT FORCE!
Allow the clutch to cool and then proceed.
D. Remove field coil assembly (2).
Step 4: Removal of Field Coil Assembly (2)
(All compressors except HR980)
A. Separate electrical connection and, if applicable, remove clutch wire retaining clip from the compressor.
B. Remove field coil snap ring (3) retaining the field coil.
C. Remove the ground screw on the compressor, if used.
D. Slide the field coil (2) off the compressor housing.
Installing Clutch on Compressor
Replace the complete clutch to ensure required performance is achieved and warranty requirements are met.
Step 1: Preparation of Compressor
A. Clean compressor nose of all dirt, grease or debris. Check for evidence of oil leakage from the front seal and through bolts of the compressor. Repair or replace compressor as appropriate.
B. Check mounting surfaces for nicks, burrs and scratches (See Figure1). Smooth with a file or emery cloth, if necessary.
C. Make an electrical system check with all electrical accessories turned on to ensure that the voltage available to the clutch is 10.8 volts minimum.

and more http://www.warnernet.com/pdf/819-0316_P-1401.pdf

Troubleshooting Checklist
For failure diagnosis of the clutch being replaced, (the failed clutch), refer to the Warner ElectricTroubleshooting Guide (form P-1011) and the appropriate A/C manufacturer's Service Manuals.
Use the guide below to troubleshoot the new clutch.
A. Symptom: Clutch will not disengage
Possible Causes Solution
• Improper hub/armature to rotor/pulley • Reset air gap (See Figure 7)
air gap (too small)
• Current is always on • Check electrical system
• Rotor/pulley snap ring not installed • Install per instructions (See Step 2)
correctly
B. Symptom: Clutch will not engage
Possible Causes Solution
• Improper hub/armature to rotor/pulley • Reset air gap (see Figure 7)
air gap (too big)
• Field coil electrical wiring is not connected • Connect field coil wiring
• Faulty field coil • Check field coil for continuity
• Less than 10.8 volts supplied to field coil • Check electrical system
(all accessories on)
C. Symptom: Clutch is noisy
Possible Causes Solution
• Field coil or rotor pulley snap rings • Check for correct installation (See Step 2) are not installed correctly
• Belts too loose • Tighten per A/C manufacturer’s service manual
• Bearing noisy (new clutch only) • Return to manufacturer
• Clutch not burnished • Burnish per instructions (See Step 5)
D. Symptom: Clutch slips
Possible Causes Solution
• Belts too loose • Tighten per A/C manufacturer’s service manual
• Voltage to field coil less than 10.8 volts • Check electrical system
(all accessories on)
• Improper wiring or connections • Check electrical system
• Oil or grease on friction surfaces • Replace clutch
• Clutch not burnished • Burnish clutch per instructions (See Step 5)
http://www.cpsproducts.com/site/elem...20AC10868A.pdf

that is probably the right tool (?)
Mastercool Nippondenso Clutch Plate Remover MSC91011
http://www.denlorstools.com/home/dt1...e_remover.html

Edit:
here is a cheap set with even a holder
http://www.powertoolsonline.net/delu...chtoolkit.aspx
Deluxe A/C Compressor Clutch Tool Kit

List Price: $124.95
Your Price: $54.36
You Save: $70.59 (56 %)
Manufacturer: CPS Products
Manufacturer Part No: CPSCTK1300A
Features:
Combo installer/remover tools
Service manual with ID chart, air gaps, and torque specs included.
FREE Universal Spanner Wrench included.
Removes/Installs: GM R4, A6 SAE; GM V5, DA6 HRG Metric; Ford FS6/Chrysler C171; Hitachi MJ/Tecumseh; Nippondenso 6P/10P.
Also Removes: Sanden SD 5 & 7; Zexel (Diesel Kit)


BUT, they do not offer international shipping.
I found all these with the search : Nippondenso 10P Remover & Installer

http://www.thefind.com/cars/info-a_c...ool-kit#page=1

[shogun]

measurements takes from the worn clutch part of my car from 11/88 and the parts car one from 03/1994 E32 750iL, you can see that there is no more 'fat' on the clutch and also the distance shims/washers
http://www.bimmerboard.com/members/take/2.JPG
http://www.bimmerboard.com/members/take/3.JPG
http://www.bimmerboard.com/members/take/4.JPG
http://www.bimmerboard.com/members/take/1.JPG
http://www.bimmerboard.com/members/take/0.JPG

next weekend we will continue to try to repair it with parts from the parts 750. But we want to try to repair it, not just change the complete compressor.

[shogun]

not fixed even with new (old) clutch

well today we took off the outer and inner clutch parts.
no special tools but it took some time to get the right jam point to take the end bolt off. The inner circlip was a real pain in the butt to remove.

We swapped with the same parts from our 91 parts car. On the 91, the moving inner clutch slides smoothly with no side play. On my A/C, the inner clutch wobbles so we can only assume that the shaft itself is worn. We checked the bearing on the original inner clutch and the bearing is not badly damaged - spins smoothly.
cause of noise:
judging from the rub marks on the coil pack, it is being hit by the inner clutch.

may be time for a new compressor assembly with new clutch.
Anyhow. great weather so we had a comfortable wrenching Saturday. Final event was a visit to a local hot spa. A great way to relieve all the aches and sprains of the day.

[shogun]

We just finished to change the ac compressor, now I have one in from an E31 850, but had to change the pulley on the compressor as the 850 has a different pulley with space for 2 belts as it has 2 alternators.
Finally this clicking noise is gone, it was the compressor shaft, too much wear on the surface where the pullry and clutch are, pulley was wobbling on the shaft, also tried the 850 pulley on the defective compressor to confirm that the shaft was the problem, also wobbling, on the new compressor the old pulley is fine. I hope no gas leaks, but that we will see and have to watch the next weeks.
Took about 4 hours, worked in our pit which helped a lot to work from underneath the car, quite difficult to losen the 2 6 mm torx bolts for the ac pipes on the compressor,that took most of the time, they were really tight and little space to get to them with force.
Vacuumed the system and recharged it, cold air coming, I hope that was it.

[bigcfromcinci]

Hope you got it taken care of..Sounds like a lot of time put into it.

[shogun]

we try to repair everything and if necessary eliminate weak points. Motto:
buying new everyone can do, we try to repair it, although it might take time. But we always learn from it.
In the end, when successful, it makes more fun, although sometimes we fail ;-)

[shogun]

just a question to the electronic gurus:

how to trick the lock sensor system on a 750?

That means eliminate it completely.
Reason: only the M70 engine has this lock sensor system, there are plenty of 10PA17C compressors around, but few of same type 10PA17C with lock sensor= very expensive for the 750.
There are 3 wires on the lock sensor
http://foto.arcor-online.net/palb/al...3065343564.jpg
and the lock sensor relay is behind the speaker footwell driver side.
The relay will unlock the compressor clutch in case it senses a deviation between compressor speed and crankshaft (?) is exceeding pre-specified limits.
In case there is no sensor on the compressor, then it might never kick in to work properly.
I am not the electric guy, but a question to those who know:
can one bridge the compressor sensor connectors/wires to manipulate the system that it believes the parameters are always fine?
Of course, then in worst case when the compressor bearing seizes, there would be no signal to release the clutch, that would then cause the belt to burst and other damage.
But a seized compressor bearing is - I believe- rare.

As example let's take the ETM from a 1989 750.

some background story here
http://www.bimmerboard.com/forums/posts/792377/

So is there are simple solution like just connect wire xoulor xy with wire colour zy or something like that?
---------------
BTW: I do not need such a solution now, my compressor works well, but many with a 750 would be glad if they could take one out of another BMW, standard 10PA17C compressors are available all over. The question is only how to trick the system?

edit:
I just found the EML pinout in German, and there is also the pin 44 for lock sensor connection to control unit, I assume this is to increase idle speed when compressor kicks in?

Anschlussbelegung EML M70 Bj. '92 (others before should be same)

Anschlussbelegung EML Steuergerät M70 Motor Baujahr 1992

Der Anschlussstecker EML hat die Bezeichnung X6004.

Steckerbelegung

Pin 1 EML Pedalwertgeber
Pin 2 EML Pedalwertgeber
Pin 3 frei
Pin 4 ABS/ASC/ASC+T Steuergerät
Pin 5 DME Steuergerät 1
Pin 6 EML Pedalwertgeber / DME Steuergerät 1
Pin 7 EML Pedalwertgeber
Pin 8 Instrumentenkombi
Pin 9 EML Pedalwertgeber
Pin 10 EML Stellmotor 2
Pin 11 EML Stellmotor 2
Pin 12 EML Stellmotor 1
Pin 13 RXD Datenleitung
Pin 14 Masse
Pin 15 EML Leuchte Instrumentenkombi
Pin 16 EML Stellmotor 2
Pin 17 EML Stellmotor 1
Pin 18 Hauptrelais 2
Pin 19 Masse
Pin 20 EGS Steuergerät
Pin 21 frei
Pin 22 Steuergerät ABS/ASC/ASC+T
Pin 23 Steuergerät ABS/ASC/ASC+T
Pin 24 frei
Pin 25 frei
Pin 26 EML Stellmotor 1
Pin 27 EML Stellmotor 1
Pin 28 EML Stellmotor 2
Pin 29 frei
Pin 30 Masse
Pin 31 Kühlwassertemperaturfühler
Pin 32 EML Pedalwertgeber/DME Steuergerät 2
Pin 33 DME Steuergerät 2
Pin 34 EML Stellmotor 2
Pin 35 EML Stellmotor 1
Pin 36 Hauptrelais 2
Pin 37 Hauptrelais 2
Pin 38 EML Stellmotor 1
Pin 39 frei
Pin 40 EML Stellmotor 2
Pin 41 Klimaanlagenrelais
Pin 42 Getriebewählschalter
Pin 43 Schalter Geschwindigkeitsregelung
Pin 44 Steuergerät Lock Sensor
Pin 45 Kühlwassertemperaturfühler
Pin 46 EML Pedalwertgeber
Pin 47 DME Steuergerät 1
Pin 48 frei
Pin 49 DME Steuergerät 1
Pin 50 DME Steuergerät 2
Pin 51 frei
Pin 52 EGS Steuergerät
Pin 53 ABS/ASC/ASC+T Steuergerät
Pin 54 frei
Pin 55 TXD Datenleitung

[E32FAN]

Details are on pg 6450-22 & 23 at http://www.e38.org/e32/e32_88_etm.pdf

I would open the A26 Lock Sensor Control Unit and solder a jumper wire across the Normally Open relay contacts. This will short X80 pin 3 to X77 pin 1 (shorting SW/RT/GE to SW/GR).

If there are no pulses from the reed relay in the compressor (because the new compressor has no reed relay) then A26 will de-energize its relay, but we won't care because the contacts are now shorted.

This will allow the compressor to run whenever K19 is energized and the pressure switches B7 and B8 are closed (just as in 735iL)

In later years, A26 was modified. The connector became X9968 which is not documented in the connector Views 8500. See 6450-22 at http://www.e38.org/e32/e32_92_etm.pdf

I do not see any outputs from A26 that will bother EML, so I would not expect any problems from shorting the A26 relay. The SW/GR wire to EML is just the compressor run signal to inform EML that there is a compressor load.

[Prospeeder]

yikes i dont know why i didnt catch that, but, if its noisey when the a/c is on but quiet if the a/c is off, its NOT the clutch. there is a bearing for the pully when it freewheels, and the bearing isnt under any load when the a/c is on, meaning if it is only noisey when the internals of the compressor are spinning its an internal compressor issue.

[shogun]

it can be the clutch and usually is the clutch or the clutch bearing. That was also what I thought, as we prepared for all possibilities, we even had a new clutch bearing on stand-by, but not needed.
Genereally one can say: if compressor is on with clutch kicked in (you can see that in the engine room kicking in and out) and makes noise, and no noise when clutch is not engaged: high probability it is the clutch bearing.
In my case however it was definitely not the clutch bearing, as the noise was gone when we put the clutch with the old bearing on the used compressor of the E31 850. Result and measured: the shaft of the compressor where the clutch bearing is moving all the time got thinner over the period of 22 years, with the effect that the bearing had play and wobbled. Also keep in mind that the clutch material is getting thinner and thinner over the years.

More info from E32Fan in case someone wants to use a normal compressor on his 750 without the special lock sensor:

Hi Burch.

I know what you mean about being certain - I once cut the wire for my E32 Central Locking Deadlock circuit, but I got it wrong and the car Deadlocked on me anyway and I had to smash a window to get back in. So like you, I have been extra-careful ever since!

I see that you own a 1989 750iL so you have the original design of lock sensor module.

This diagram shows where the Jumper needs to be soldered. If you remove the module cover and plug it into the sockets, you can trace the BLK/RED/YEL and BLK/GRY wires and see that they lead to the relay contacts.
https://ibb.co/Z6y5GtD

http://s1011.photobucket.com/albums/...=BMWJUMPER.jpg
[IMG]file:///C:/DOCUME%7E1/COMPAQ%7E1/LOCALS%7E1/Temp/moz-screenshot-23.png[/IMG]

If this is still not clear, I may be able to take real photos of an actual module for you.

- Steve
------------------------
that is the answer from E32Fan

[LabGuy]

Mine started making noise which sounds like ball-bearings rolling around in a tumbler when the car is turned off. It spins for about 15-20 seconds and makes the sound. Everything else works fine. I figured the pulley was going bad and noticed that there are some loose what seems like washers on the front. It's hard to see and I figured I'd just replace it down the line but since you've investigated the innards any ideas?

[Poncholarpez]

mine only does it under load from about 3500-4000rpm onward...sounds horrible from inside the car, would hate to think what it sounds like outside. Atleast I think its the a/c main unit as the noise is hardly even there when i turn off a/c & circulation switch.

[shogun]

you have to check it. The clutch is available as separate item with the pulley from specialised online shops, also the bearing.

TROUBLE SHOOTING GUIDE

http://www.polarbearinc.com/Trouble1.htm

excerpt:
....... and how does it work?

You can not effectively repair something unless you have an idea of how it works. Keeping it as simple as possible, I will attempt to clarify as much as possible about how your air conditioner functions.

There are five basic components in an automotive air conditioner:

Compressor - Nothing more than a pump. It has suction and discharge and is driven off the engine by means of an electromagnetic clutch. The clutch consists of a coil that sits behind a pulley, which sits behind a drive plate or hub. When the coil is energized it creates a magnetic field through the pulley which draws in the drive plate. The drive plate turns with the pulley, courtesy of the magnetism, and runs the compressor. Compressors may be purchased remanufactured (or rebuilt) or new.
Drier - Sometimes called receiver drier or accumulator. When installed in the liquid line it is called a drier. When installed in the suction line it is called an accumulator. Its purpose is threefold:
A.) To trap moisture (water and gas will eventually create acids which will lead to leaks)

B.) To provide a space for liquid to collect in reserve for the evaporator OR in an accumulator system, a place to separate vapor from liquid, insuring that minimal liquid (damaging) gets back to the compressor

C.) To act as a filter and trap any foreign matter which may be in the system.

Although driers and accumulators can be remanufactured (or rebuilt) they are generally sold new because they are relatively inexpensive.

Condenser - The coil in front of your radiator. It serves as a heat exchanger and dissipates the heat collected by the freon after it was vaporized in the evaporator and compressed in the compressor. It accomplishes this by utilizing air flow across a series of tubes. Condensers are only sold new.
Expansion Valve - The restrictor or metering device which limits the flow of liquid into the evaporator so that the high pressure liquid from the condenser enters the evaporator as low pressure liquid so it can evaporate or boil off into low pressure gas. Expansion valves and tubes are only sold new.
Evaporator - The coil inside your dashboard. It also serves as the heat exchanger where the Freon collects heat as the gas is vaporized. The use of air flow across the coils collects heat from the air in the passenger compartment. Although in years past different companies came to market with remanufactured or rebuilt evaporators, in our opinion they were less than satisfactory and should be avoided. New aftermarket evaporators of high quality are readily available at reasonable prices.

[Mikesuth]

Mine started making noise which sounds like ball-bearings rolling around in a tumbler when the car is turned off. It spins for about 15-20 seconds and makes the sound. Everything else works fine. I figured the pulley was going bad and noticed that there are some loose what seems like washers on the front. It's hard to see and I figured I'd just replace it down the line but since you've investigated the innards any ideas?

Hey, Labguy! I have exactly the same problem. Did you ever find a fix?

[VincentKreed]

I just replaced my AC compressor also. Once replaced with a new compressor I also have this low hum with the AC is on, but it only makes this noise when the car is idle, not when driving. I am hoping that after a closer look this will be an easy fix.

Vincent

[shogun]

Honking/Hooting A/C expansion valve
The following air conditioning information was copied from BMW’s AG TIS CD. Notice date was October 1994.

Group 64; 64 01 94 Woodcliff Lake, NJ; October 1994; Heating and Air Conditioning; Product Engineering

SUBJECT: Honking/Hooting from Air Conditioning Expansion Valve

Models: E34, E32, E36 from 9/92 to 4/94 production.

Situation: Complaint of intermittent loud honking or hooting noise from A/C expansion valve.

Affected Vehicles: E34 vehicles equipped with R-134a A/C refrigerant (since 9/92 production). In addition, we have received a few complaints with E32 and E36 vehicles. The new expansion valve was incorporated into production on E34 vehicles as of 4/94.

Cause: Expansion valve can be excited into resonance under certain operating conditions.

Solution: If a customer complaint of honking or hooting from A/C is encountered, replace the expansion valve with P/N 64 11 8 362 851. This unit employs a friction damper to prevent the valve from resonating.

Parts Information: Modified Expansion Valve w/Damper- P/N 64 11 8 362 851

Warranty Status: Parts and labor are reimbursable under the terms of the applicable BMW New Car Limited Warranty

Defect Code: 64 51 12 39 00

[shogun]

some more info for AC problems
http://forums.bimmerforums.com/forum....php?t=1403588
R134a retrofit http://www.bmwe34.net/E34main/Upgrade/AC_upgrade.htm
reasonable priced reman compressors
http://www.discountacparts.com/addto...t~60-01483.asp

A/C clutch bearing DIY
http://www.bimmerboard.com/forums/posts/858414

What's wrong with "drop-ins"?
http://www.koalamotorsport.com/tech/...nditioning.asp

[shogun]

750 lock sensor 3 pins compressor vs 1 pins compressor - my research
Author: Johan750 Posted on: 2013-01-17


As the pump in my 750 seems to leak uv dye around the compressor seal I got myself a new one. Later I saw the new one has only 1 connection in the electrical plug and thus missing the speed signal. And of course no where to mount it so I can't transplant is.

So I did some schematics checking and came up with the following:

There are two types of lock sensors. The first one was used with the R12 upto 09/91. The second after that with R134a. As these have different plugs they don't "officially" interchange.

The part numbers of the old/R12 one in order they apeared:
61 35 1 382 833
61 35 1 388 718
61 35 1 390 899
The part numbers of the new/R134a one in order they apeared:
61 35 1 392 410
61 35 8 360 039

The pin-out of the first type (two connectors):
x80-1 -- BL - to compressor rpm sensor
x80-2 -- BL/BR - to compressor rpm sensor
x80-3 -- SW/RT/GE - 12v from compressor relay

x77-1 -- SW/GR - To compressor clutch
x77-2 -- GN/BL/GE - 12v in Run/Start Fuse 29
x77-3 -- BR/SW - ground
x77-4 -- SW - to DME, EML,..etc. engine rpm

The pin-out of the second type (one connector):
x9988-2 -- BR/SW - Ground
x9988-3 -- SW/RT/GE - 12v from compressor relay
x9988-4 -- GN/BL/GE - 12v Run/Start Fuse 29
x9988-5 -- SW/GR - to compressor clutch
x9988-7 -- BR/GE - tap on cluster (x16-24) engine temp sensor
x9988-9 -- BR/VI - tap on cluster (x16-26) engine temp sensor
x9988-10 - SW - DME, EML, cluster,..etc. engine rpm

According to the ETK I need a new lock sensor 61 35 8 360 039 and an adapter wiring set 64 52 8 391 881. My guess is that the adapter wiring set goes between the car and the new lock sensor.
But as the compressor cost enought and I recently had the chance to pick some parts off a 93 750i I am now the proud owner of a 61 35 1 392 410 lock sensor with loose some wires.

So my plan is to splice the new plug into the wiring of the car, leave the temperature wires alone thus enabling me to use the newer lock sensor which doesnt need the compressor speed signal. If this doesn't work I'll tap into the cluster temp sensor and then it's 100% identical to the 92 upwards model years ans must work.

It seems to me in theory there are two other ways to bypass the old lock sensor:
1) Wire the input 12v from the compressor relay to the output to the compressor clutch thus bypassing the sensor
2) Also cut the x77-4 black wire so the lock sensor reads the compressor speed as 0 (as there is no speed sensor) and the rpm as zero (engine not running). This could fool the unit as it matches to two signals and disengages when the speed difference is 30% or more.
-->Both methods disable functioning of the sensor completely so use at own risk!

I found some postings on the net from Shogun and Hitmax which pointed me in the right direction. But as I collected all the part numbers and pinouts I though I'd share it just the same.

-Johan-

[affa]

I'm attempting the same feat here.... on my E31

My car came from the factory on R12, converted to R134a by the previous owner (via dealer). The original compressor has the rpm sensor. New compressor hasn't.

1. Found the lock sensor and its of the 2nd type 61 35 1 392 410. all good so far.
2. On the connector (what the E32 calls x9988), I have all the same wires. In addition, pin 1 and 6 are occupied by the rpm sensor wires.

No im wondering whether the compressor without rpm sensor will operate correctly on the 61 35 1 392 410 lock sensor.

Erich - What was Johan's result on using the 61 35 1 392 410 with the compressor without rpm sensor?

[shogun]

Hi Affa, E32Fan has given here detailed instructions how to to. http://www.bimmerboard.com/forums/posts/885452/
Lock sensor is in my opinion not absolutely necessary, it is just a safety feature in case the compressor blocks/breakes/seizes.

I do not know what Johan finally made. But as he is also registered now here, he will probably reply by himself.

[shogun]

Update: after 4 years my repaired compressor still works very well. No problem at all and no more wobbling and noise.