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Does anyone know the physical difference between the Air Conditioning compressor for a 12 v and a 24 v 164 3 litre engine apart from the 24v running 134A Freon. The A/C compressor has failed on my 95 LS and I am looking for a replacement rebuilt unit and can find them all on the web but nobody seems to know what is different between model years.
 

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1991 164L
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SD-709 and SD-7H15 Alfa 164 AC compressor info

Differences external are crankshaft threaded end outer diameter size and clutch pulley width and clutch plate internal diameter of end that fits onto threaded shaft of compressor crankshaft.

If you had both you could probably use clutch coil from either one, clutch plate has to match crankshaft size and clutch pulley can be either 7 wide for 24v or 7x5 wide for 12v crankshaft one. Length of crankshaft for clutch looks the same, too.

Lug spacing the same for mounting.

Internally piston size and displacement maybe different as 12v SD-709 and 24v SD-7H15.

That maybe 9 cubic inches vs 15 cu in.

I am not sure about internals but do know crankshaft threaded end OD is different 24v smaller than 12v compressors.

This website appears to have one for 24v 164:

Special order SKU: 100820 Part No: 30989 - AC Compressor | Evaporator Core | Fuel Pump | Condenser | Water Pump | Clutch

SD-709 model 7461 91-93 Alfa 164 12v V6 has 119mm PV7x5 clutch pulley.

SD-7H15 Model 7835 94-95 Alfa 164 24v V6 has 135mm PV7 clutch pulley.

Both have CB head with two vertical ports same size.

Ear mount - Lug spacing is the same.
 

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1991 164L
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more pix

More pix of SD709/7H15 compressors.
 

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Part 30989 on that site shows up as the Sanden SD-709. Would that not be the 12V compressor?

Internally piston size and displacement maybe different as 12v SD-709 and 24v SD-7H15.

That maybe 9 cubic inches vs 15 cu in.

I am not sure about internals but do know crankshaft threaded end OD is different 24v smaller than 12v compressors.

This website appears to have one for 24v 164:

Special order SKU: 100820 Part No: 30989 - AC Compressor | Evaporator Core | Fuel Pump | Condenser | Water Pump | Clutch

SD-709 model 7461 91-93 Alfa 164 12v V6 has 119mm PV7x5 clutch pulley.

SD-7H15 Model 7835 94-95 Alfa 164 24v V6 has 135mm PV7 clutch pulley.

B
 

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1991 164L
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27,586 Posts
Part 30989 on that site shows up as the Sanden SD-709. Would that not be the 12V compressor?
Yep, the SD-709 12v with 7x5 pulley clutch is what comes up. Proves you can't use their search feature by putting in 94-95 164 and get correct item.
 
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