I have an '02 Durango, and the AC only blows cool air when going down the road at 25+ mph. I thought I’d try putting some refrigerant in, but when I hooked up the gauge on the can it buried the needle, so it’s over 100 psi on the low side, and the pressure was high enough that no refrigerant would flow in. Up where the lines attach to the expansion valve, when idling the in line is HOT - like too hot to keep your hand on and the out line is about air temp. The guy at the parts store thought the expansion valve was bad. As stated, AC works okay (but not excellently) while going down the road. Thoughts?
Is the electric radiator/condenser fan working? If there is more than 100 PSI on the low side I suspect the compressor was off due to high system pressure on the high side.
I just put in a new electric fan a few days ago, and it is working.
I’m assuming you’re using one of those single use cans with a short charging hose? Offhand, it does sound like an expansion valve problem or possibly an overcharge problem, but my preference would be to know what the high side pressure is before condemning anything.
This may not be the problem either but I’ll throw it out there anyway. Sometimes the service port connection doesn’t fit the charging hose connector very well and the pressure you may see is not the system low side pressure but the pressure in the can.
It is strongly recommended that you wear gloves and safety glasses if you are not doing so. The possibility of a can explosion always exists and more so if there’s a pressure problem on the low side. Refrigerant in the eyeballs can cause permanent blindness in half a second.
Sorry I can’t be of more help. Not knowing the high side pressure muddies the water a bit.
The in line can be hot because the pressure is still on. When the refrigerant expands after it goes through the valve, cooling will occur. The evaporator then transfers the cool temperature to the air. Is the AC fan working? If there is cooling when the car is moving, it’s because there is air going through the condenser. No fan = no cooling.
Expansion valve failures on Durangos usually get stuck closed resulting in very low pressure on the low side. If the clutch is engaging and you have this high pressure the system is over charged or the compressor failed. You need real gauges to diagnose this.
@Nevada_545 , that was exactly the problem with my brother’s '92 Celica. Low side pressure was way low, but high side was through the roof. We wound up taking the system apart to replace the expansion valve, and checked the lines for blockages but found none. Once the system was back together, evac-ed and charged, it was super cold. If the high side and low side are close to equilibrium with the compressor running, check to see if the clutch is slipping. Otherwise, it may be the compressor.