After having great experiences with two 740 volvos, I recently purchased a 1995 850 wagon for my 17 yr old daughter. Tried out the air conditioning today. The compressor kept turning on and off every 3-5 seconds and the air coming from the vent was not cold at all. I hooked an ac recharge kit to the low side port. As thecompressor turned on and off the reading was 45 to 65 psi. The reading fluctuated as it turned on and off. I let out some of the refrigerant and turned on the ac. The compressor didn't come on at all and the reading was 20 psi on the gauge. The air coming out of the vent was still the same temp as before. I added some refrigerant totry and get the correct psi reading (25 to 45). When the gauge got to 25 psi the compressor began to turn on and off again every 3 to 5 seconds and the reading on the gauge fluctuated between 25 and 45 psi. The temp of the air coming out of the vent remained the same. I have no background on this vehicle from the previous owner. any help would be greatly appreciated.

 

The reading should be in the 30ish range (it depends on the ambient temperature) with the compressor running and the compressor shouldn't cycle like you describe. It should be around 100 psi (again, ambient temperature dependent) with the compressor off.With the compressor off it pretty much pegs the recharge kit type gauges and scares the hell out of people.

You need more R-134A and then you can see how long it lasts. If it lasts a summer season then a couple of cans ofR-134A per year is cheap. If it only lasts a few days research "evaporator replacement". It is a big job.

...Lee