91 Volvo 240 AC compressor choices

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wcirco
Posts: 2
Joined: Thu Jul 09, 2020 10:43 am

91 Volvo 240 AC compressor choices

Postby wcirco » Thu Jul 09, 2020 11:49 am

Hi everyone
I have a 91 volvo 240 with the later style orifice tube AC system. I recently installed a rebuilt oem compressor purchased from ebay along with a new evaporator core, accumulator and orifice tube. I thoroughly flushed the condenser and hoses. The system pulled down to 500 microns and held below 700 for 5 minutes. Mineral Oil and R12 were used. When I first charged it, it blew ~50-55 degrees at idle and low 40s while driving. Pressures were perfect at 30 low and 220 high and the compressor would cycle regularly while driving. Now after a couple weeks I cant even get 70 degrees at idle and 60 while moving. The compressor is no longer cycling. My first thought was a leak but the gauge readings prove otherwise. Today with 90* ambient I'm seeing 50 on the low side and 130 on the high side. If I rev the engine to 1500 rpm it drops to 40 on the low side and goes to 150 on the high side. Even held at 3000 rpm I cannot get the low side pressure below 30. I'm fairly sure my compressor is dying. Having realized buying a cheap reman was most likely my problem, Id like to pick out a new compressor this time around. However there are two different types of ac compressors they sell for these cars.

The first is the OEM Diesel Kiki style unit like this: https://www.partsgeek.com/gbproducts/DC ... p=pp&gbm=a

The second type is a Sanden compressor : https://www.acparts.com/product/new-ori ... ssor-4664/

The question I have for the experts: Which type of compressor am I better off with? I'm leaning towards the Sanden as it seems like a more modern compressor. Any input is appreciated!
Al9
Posts: 153
Joined: Tue Mar 10, 2020 3:26 am

Re: 91 Volvo 240 AC compressor choices

Postby Al9 » Thu Jul 09, 2020 12:50 pm

The Diesel Kiki is a double acting piston design. That is, no isolated crankcase. It depends upon a steady supply of oil from the suction gas so that it can be picked up and then sent to any moving part within the compressor housing. 100% splash lubrication. Hence, an abnormally high superheat condition (such as running the system with an awfully low refrigerant charge) means low oil return, which in turn means some serious wear.

The Sanden, on the other hand, is a single sided piston design. It has an isolated crankcase that is able to store a good amount of oil in any operating condition. You can see this by yourself, there's an oil drain bolt (what double acting piston compressors such as the Diesel Kiki often lack unless they come with a sump and a dedicated oil pump, such as with the Seltec TM31). This makes this compressor design a little more tolerant of low refrigerant/low oil return related abuse.

For this reason, i'd prefer the Sanden design over the Diesel Kiki one. More reliability, more ruggedness.
Last edited by Al9 on Fri Jul 10, 2020 7:28 am, edited 1 time in total.
wcirco
Posts: 2
Joined: Thu Jul 09, 2020 10:43 am

Re: 91 Volvo 240 AC compressor choices

Postby wcirco » Fri Jul 10, 2020 6:24 am

That makes sense, the Kiki compressors have a reputation for wearing out quick. Although looking the original one I removed it does have drain and fill plugs. The model is a DKS-15BH. I recall just adding oil to the compressor per the volvo specs.
This morning I decided to recover and open up the system. I found brown junk in the orifice tube screen that seems to be dirt?? :shock: Not sure how it got in there unless it was in the new evaporator or accumulator. Definitely explains the compressor failure though. Lesson learned, flush new components too.
I'm going to give the Sanden 4664 a try the second time around. Hopefully with some luck and lots of ac flush I'll have comfy 40* air again :mrgreen:
Al9
Posts: 153
Joined: Tue Mar 10, 2020 3:26 am

Re: 91 Volvo 240 AC compressor choices

Postby Al9 » Fri Jul 10, 2020 7:43 am

You're right, the DKS and TM auto sized units feature dedicated oil drain/fill ports. Perhaps it's meant to make the oil drain/fill process easier and quicker.

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