The guy at the automotive store told me that my A/C refill won't work because the system on my Volvo 850 1996 Wagon hasn't been upgraded, so the valve from the refill can doesn't attach. My Volvo mechanic, very reputable, said he didn't know what we were talking about. He can replenish the A/C for $220. Does that sound right? Do I need to get my system upgraded - and what's involved?

Thanks,

Chris

 

The guy at the automotive store doesn't know what he's talking about.

 

+1. I've topped off my 95 850 several times. The low side port is on the passenger side - just follow the return line from the firewall back towards the compressor. A standard refill kit hose will fit to the low side port. The only trick to know is that the compressor needs to kick on to pull in the refridgerant and if you system pressure is too low, you need to jumper the low pressure sensor. You will also find that on the return line tracing back from the firewall.

 

Thanks so much. I did get the valve to fit but the coolant is not going in and the gauge immediately goes to red. Any more thoughts? Also, how do I "jumper the low pressure sensor"? Thanks so much for your help.

c.

 

Sounds like you need an AC shop.

DIY is fine if you know what you're doing, but if not, you'll just break things and contribute to the ozone problem.

 

to jumper the low pressure sensor, find the sensor/connector on the return line (tracing from firewall to compressor on the right (passenger) inner fender). Disconnect the connector and use a paper clip to bridge the two connections. Follow the directions on the kit, noting the correct pressure for your ambient temperature (ie air temp). The process will be something like 1) Jumper the connector 2) Hook up the refill kit with gauge to the low port - leave closed. 3) Start the car, set AC on, full cold temp 4) open valve to measure pressure 5) orient can to flow refridgerant/oil to flow into hose (see directions if its done with an upside down can) 6) open valve to flow charge into system monitoring pressure. 7) close all valves, stop engine, remove paper clip and reconnect sensor. 8) restart and see if compressor now kicks on and whether pressure is now in correct range.

Note that this is only for topping off once in a while. If you need to recharge more than once every few years, you probably have a slow leak which should be professionally serviced. Refilling to top off refridgerant pressure more than once in a great while will mess with the correct about of oil in the system and risks damage to the compressor. Professional service would check for leaks, replace o rings, orifice valve, accumulator/dryer and vacuuming the system to pull out all moisture and air, then charging with the correct amount of oil and R134.

 

@mt6127 I don't understand? You're telling him to jumper the low pressure switch w/o even checking to see if it needs to be jumpered (i.e. is it open?). I've never had to do that to get freon into the system. And he states above that the gauge is in the red zone. This indicates too much pressure (i.e. freon) in the system; not too little. I.e. there's already too much freon in the system (apparently). He likely has other issues besides just low freon. That's why I suggested he get professional help with this.

 

Since there's no high side port, you really don't know what you are getting in to with these symptoms.

That said, if you didn't start the engine, that would at least make some sense out of the symptoms here. Or, if the clutch wouldn't pull in because of a local problem with the clutch (common volvo problem). You have to get the compressor turning if you already have high pressure, and you may not need any freon.

If the compressor is not turning, then you don't know whether you've got too much freon or not. Don't jump to conclusions.