The A/C on my 94 NA 850 with manual climate control stops cooling when outside temps are above 86 F or 30 C. Evaporator has been replaced recently and the system is not leaking. What could be the cause? When it is cooling it colls fine. What usually happens is that after sometime of operation, suddenly, air gets warmer and warmer. Blower operates normally. If I leave controls untouched,it does not get cool again. If I turn of the compressor switch for a few minutes, and turn it on again, it colls again.
I know this is a relatively common problem in the 850. Anyone knows what is wrong. It is now summer in my country and driving without the A/C is no fun at all. Also, there are no Volvo dealers where I live, so I am very much on my own to get this thing back to normal.
Thanks

Icelandic,

I replaced my evaporator this past summer because the leaks got too bad. I did not have any problem with the a/c compressor cutting out because of very hot weather until about a month after the new compressor was installed.
I also did not replace the dryer/ receiver and do seem to have any prolem with it. The car had approx. 125k at the time. '95 855t.

By the way, I cannot take full credit for the post on the disconnecting of the hitemp cut out swicth, A fellow brick boarder by the name of Arron See originally posted this and it is talked about in the archives of this board along with a life times worth of similar vital information on Volvos and their peculilarities!


steve d.

my 96 850 did the same thing last summer, after carefully reserching all the posts I decided to put in a new compressor. dealer told me new evap and compressor, well guess you can imagine how much that would cost. anyway I told mechanic to replace the compressor for 900 dollars at dealer and its been working great ever since. sometimes your better off making the call yourself and with the help of others. kelly NJ

The compressor on that car has a temp cutout switch on rear of compressor. When the refrigerant falls below the 100% full level the compressor cooling effect of the refrigerant is diminished and the cutout will interrupt compressor operation on days over 90 degrees (can happen when refrigerant level is full when temp goes over 100).
The switch can be bypassed as the system has other protections built in and new compressors from Volvo no longer have the switch. The refrigerant level should be checked as well.

It is hard to get to connectors as there isn’t enough room for bigger hands.
Look at the compressor from under the car looking between the oil filter and the frame, and see the cut out switch with two wires coming out of it, the switch looks as though it is screwed in to the compressor.

All you have to do is to bypass or eliminate the sensor/switch
1.Remove connectors and unplug them. Connectors have male and female plugs.
2.You will have 4 sets of wires after unplugging connectors.
3.Reconnect the two wires that will alow you to bypass the switch and leave the two wires hanging from the switch.

All you are doing is to disable the sensor/switch and connect 12VDC to the compressor.

Good luck,

steve d. '94 850, 120k, '95 855t, 140k, '00 c70, 77k.

Thanks for the very good directions Steve. You appear to be very knowledgeable about the A/C system, so if you do not mind I have a couple of questions: 1- When the car was newer, I never had that problem. Would normal use cause the compressor to develop a tendency to overheat, triggering the temp cutout switch? (my car has 155k miles on it)

2- When the evaporator was replaced, the A/C shop said that the accumulator was OK, and they did not replace it. Could it be bad, somehow causing the compressor to overheat? Could it be caused by any other component such as oriface tube etc?

Thanks

When they replaced the coil ,if some moisture got in there ,it could freeze up
the unit when the unit gets real cold . Shut if self down then be ok once it thaws

It sounds like what my a/c did when the compressor was going bad. You will have to take in to a shop to get this correctly diagnosed, in my opinion. However, any indi shop with experience with this type of a/c should be able to diagnose and repair. If the compressor is replaced, the receiver dryer must be replaced also. Often the orifice tube will be replaced at the same time as well.

Phantom