850 AC - A different problem?

Is the evaporator drain plugged? On very humid days you should be able to see the water drip and run out from underneath the middle of the car.

Robert, Could be Evaporator icing........ Dale Peterson

I was thinking it might be something like that, icing over of the evaporator.

That isn't the usual sign of failed evaporator, is it?

Is it fixable?

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-RL

Doesn't the '96 have the infamous compressor overtemp cutout switch? IIRC they got rid of it in later years, but earlier 850s had the troublesome switch on the rear of the compressor. They didn't seem to save compressors, just cause symptoms like yours. The gurus will probably provide the details.

Mike

Yes but if the car has a pollen filter check this also this will keep the evaprator from breathing if it is clogged

Clutch gap. I've just done mine during the heatwave and bypassed the temp cutout at the same time. Gap should be 0.3 to 0.5mm and mine was something like 1.2mm.

It's a bit of a pig to do as I found that I had to remove the ECU's the ECU box, the belt, the power steering pump, the alternator and the brackets for same before I could get to the compressor, then the compressor has to be unbolted to get enough room to take the pulley off just so that you can remove a shim.

Still it was worth it in the end.

David.

If icing was the problem, the airflow would go way down. Also, icing is usually a sign of low refrigerant charge (At lest it was on my home's system)

If it's the overtemp switch, the cooling will come and go, over about a 5 minute cycle. I didsonnected the switch on my 94 years ago, and haven't had a problem since.

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My 960 did exactly the same thing, and it turned out to be a $15 temp sensor at the rear of the engine.

Don't know whether the 5-cyl version of this engine has a similar sensor / Motronic setup.

Based on the symptoms, I'm guessing it's the overtemp switch on the compressor. Thanks to all who responded.

Is the overtemp switch a little square molded yellow thingie, about 1cm square sitting atop the compressor?

Thanks,

-RL

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Another cure for the clutch gap is to put a relay in the circuit. This gets a higher voltage to the clutch winding, delaying the repair for ???

Disconnect the wire that leads to the compressor clutch. The wire that's part of the compressor goes to pin 87 on your relay The wire that's part of the engine harness goes to pin 86 on your relay Pin 85 on the relay goes to ground. Pin 30 goes to a fused power source. This circuit only draws about 5 amps.

The cutout has 2 wires going into it and is mounted on the back (non drive end) of the compressor.

Yes but the amount of effort to do that (and extra pennies) :) when all I had to do was spend several hours doing it properly just doesn't compare!

(yeah it's a pig but I like to do things once).

David.

No, it's underneath and round the back, tricky to get to.

David.

It has two wires, with male and female connectors, which connect between the car's wiring harness and the clutch wire. All you have to do is unplug the two connections, and plug the clutch wire directly into the harness wire. The connectors have split plastic covers on them which keeps them clean and secure. Having long, skinny arms helps.

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Ah it was the skinny arms that I fail on and besides, I had the compressor in my hands at the point when I decided to bypass it. I was already doing the clutch shims.

David.

While I agree "your" way is the better way to do it, "my" way has some benefits. Volvo added a relay for this function on the S/V70 in 1998. You can do this repair without crawling under the car, or removing any other parts, a big benefit if it's hot, you don't have much time, or don't have the tools/skill. As a disclaimer, I don't know how much longer this will enable the compressor to work.

That's the thing and with my gap at 1.2mm already, I was going to do that because the problem only manifested itself during the very hot days and we don't get enough over here to keep doing trial runs to see if the fix worked and when it is hot enough, it's a bummer to discover that it didn't.

Hence, full job for me. :)

David.

How do you change the air gap? I've got a VW Passat with similar symptoms, and am planning tomorrow to try a bypass wire to test with a solid 12+ volts. If it is the clutch gap, how would it be adjusted? ( Sanden compressor)

Ron/Champ 6

The amazing power of Googling for "sanden compressor clutch gap" yields the second link as the Sanden service manual

David.