Mercedes 6.9: Options when buying a new AC compressor?

Started by jllgd, 14 March 2021, 02:40 PM


Looking to purchase a brand new high quality AC compressor for my 6.9.
Believe the original unit is of the A6 type.
Typically made back in the day by GM (General Motors).

So what options do I have for a brand new compressor?
Preferably not made in China (is that even possible these days?)

Is it correct and verified that the original unit does NOT have a superheat switch?
Should the compressor wiring connectors be at the so called 10 o'clock position or at the 2 o'clock position?

I believe it's also recommended to replace the receiver drier when doing the compressor.
Anyone having the correct Mercedes part no. for this?

Any help and input appreciated. Thanks


I've now been informed that the Mercedes 6.9 compressor part number is:
000 230 49 11.

Ac Parts then informed that this A6 compressor is the correct unit for the 6.9:

Any thoughts on this? Thanks


NEW Original GM A6 Compressor 1131242, 1134243, 1131223 (1401058)

Compressor NEW GM A6 WITH SHS W/ 5.0″ 1 GR 12V 10:00 COIL *METRIC THREADS* (1401058)

Description: NEW OEM A6 Compressor 1GR 5in 12V 10:00 METRIC THREAD W/SH SW
OEM Number: 1131223, 1134243
Manufacturer #: 51-86031A
Volts: 12V
Clutch Diameter: 4.87"
No. of Grooves: 1 groove
Belt Type: 1/2" Belt
No. Comp. Cylinders: 6 cyl
Comp. Displacement (ci): 12.6
Factory Oil Charge: 10 oz oil
Oil Type: PAG150
Fitting Port Position: Rear
Fitting Style: GM O-ring Pad
Head Type: Superheat Switch Port
Wire Type: 2:00 (RH) Plug
Model: A6
Mounting Type: Metric
Product Name: Compressor
Refrigerant Type: R12/R134a
Rotation: CW
Shaft Type: Keyed shaft
Diode Protection: None
Make: Delphi GM
Switch Type: SHS

Picture from the previous link:


I am now preparing in cooperation with the mechanic/technician for replacing my 6.9 ac compressor.

After removing the old compressor I will try to locate a brand new US made exact replacement A6 unit.

Preferably a Alma compressor as already suggested on this fine site.
Anyone know who their California distributor is?

I read also here that the 6.9 compressor does NOT originally have a Super Heat Switch (SHS).
Is this verified and correct?
Do the newer Alma compressors have a SHS?

When I have removed my old compressor, how do I know if it has a SHS or not?

I assume my compressor is Mercedes factory original to the car.
But I don't know if it still has the printed tag/label fitted, as I can't see it from underneath the car.

What clock number should the electric connections have?

Any special precautions to consider when removing the old compressor and installing the new one?

Happy to hear from those with knowledge on this subject. Thanks


There is no super heat switch.  There is not room for one.  Contact the seller as to whether or not it has one. 

Metric threads in the compressor are correct. 

At the time, the compressors were made by Frigidaire.  The decal(s), if even still present, will be on top. 

The plug connection on the electromagnet should be positioned in the 10 o'clock position since the compressor is on the right hand side of the engine. 

While the compressor is off, it is a good time to:

Renew motor mount(s), engine torque dampers and bushings, clean, and have the rubber A/C lines rebuilt if they look suspect. 

The listing you provided says that the compressor comes with 10 ounces of PAG oil.  It's best to stick with R-12 freon, as R-134A will not provide adequate cooling (condenser is too small).  In doing so, you must drain the PAG oil out of the compressor and put in 10 ounces of R-12 mineral oil.  Don't let the crazy CA repair shops tell you that R-12 is illegal to use in your car.  If they possess an EPA 609 certification, which EVERY shop should have, then they can legally purchase and use R-12 for automotive purposes. You can even buy it off of ebay and have it shipped to them.  If they give you the run around about the state of CA saying it's still illegal, then remind them that federal law trumps state law. 

And yes, you need to renew the drier and both pressure/thermal switches on the drier as a matter or principle.

Drier part number:   116-830-04-83

Low pressure cut out switch part number: 000-820-43-10 (up to chassis number 003081), and 124-820-83-10 (from chassis number 003082)

O-ring for pressure switch part number: 140-997-11-45

Thermal switch for electric auxiliary fan:  000-820-80-10

Make sure that your auxiliary cooling fan is new and/or in good working condition.  As they age they draw excessive current and will cause the plastic housing behind the climate control push button assembly to melt. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo


Thanks for your thorough reply, UTn_boy.
Much appreciated.
Those part numbers will be useful.

What about replacing the expansion valve upon the dash?
Is that absolutely necessary or just recommended?
Or should I await replacing it until it eventually fails?
I've read it's quite complicated to replace this valve due to restricted access.

We were now able to remove my old GM Delco Air ac compressor.
Car is a 1979 6.9.
It's being replaced due to an identified R12 leak at the axle shaft.
I will try to attach some pics of it.

Trying now to source a new, exact A6 replacement compressor.
The number on the compressor label says:

Delco Air
General Motors, Dayton Ohio
Model no. 1131109
Code no. 061292
S.A.E. J639
Charge R12

Would any of you know if this is available as a brand new Alma compressor?

What is the clutch coil clock number on my compressor?
The compressor model no. 1131109 doesn't throw many leads when googling it.
Very strange indeed.
Further inputs much appreciated.


We will be doing the new A6 compressor install this week.
Got all parts needed for the job, except the mineral oil.

Staying with R12, not going the R134A route.

It says the new Alma compressor contains 10 fl. oz of PAG on the compressor sticker label. See pic.

So if I am able to drain 10 fl. oz from the new compressor, should I flush and refill it with exactly 10 oz mineral oil? Or less?

On my old compressor, the sticker label also says it contains 10 oz.

I am concerned about adding too much oil to the AC system, but also too little will harm the new compressor.

So, will it matter how much oil that's being drained from the old compressor or not?
Should the drained amount of old oil be measured and compared to what's being filled into the new compressor?

What about the new receiver drier, should I add any amount of oil to it? Or add all the oil only to the compressor?

Appreciate your advice. Thanks.


1977 450 SEL 6.9 - Astralsilber