Automotive Air Conditioning Information Forum (Archives)

armymutt on Fri May 04, 2012 5:39 PM

Year: 2000
Make: Nissan
Model: Xterra
Engine Size: 3.3L
Refrigerant Type: R134
Country of Origin: United States

I'm trying to fix my A/C. I'm pretty sure the high side hose is shot - got a good soaking of oil on the rubber part. I've recharged the system a few times and the pressures do not remain right very long. I'm pretty sure the compressor is ok - it engages when I turn on the A/C. My plan is to replace the high side hose and the drier, along with any o-rings I disturb. Should I also have the system flushed? I've read that there are certain parts that shouldn't be flushed, but there didn't seem to be an agreement as to what. When I added refrigerant, the pressures came up to where they should be, but the temp of the air blowing from the vents did not drop significantly. Am I right in believing that there isn't a blockage in the system? Is there anything else I should do?

I am also trying to figure out how to test the condenser fan circuit. The fan works when voltage is applied. The circuit diagram shows it being controlled by a fusible link and a fuse, as well as a relay. I can't tell which relay, but all of them function when tested. One of the relays is marked "Rad Fan". Since the fan behind the radiator is mechanically controlled, I'm assuming this controls the condenser fan. This relay didn't have power when I tested it, but I don't know what conditions must be met for power to be applied. There is also something that Nissan calls an ambient sensor in front of the condenser that is wired into the fan circuit. I tried to jump it, but didn't get any power to the fan. Looking for ideas here as well.

rfrank22 on Sat May 05, 2012 12:22 PM

Do you have gauges? How long was the system open? Just because the compressor engages doesn't mean its ok. Internal pressures are critical and must be correct with the right amount of refrigerant in the system. The fans will come on when the coolant temperature gets above a certain threshold as well as the condenser auxiliary fan for the ac system pressures. Usually above 200 on the high side. Thank You..Richard rautoac@gmail.com

mk378 on Sat May 05, 2012 12:25 PM

Repair of a simple slow leak doesn't call for any flushing. The drier should be replaced though just due to age. Add an oz or so of oil to replace what was in the old drier and the small amount that may have leaked out (realize that a small amount of oil makes a big mess).