We have a 1995 Dodge Dakota with an A/C problem. Here is what I know. The A/C works as long as the outside temp is below 80. Once it gets above 80 the A/C starts to blow warm. We thought it was low on refrigerant, so we bought a few cans of it. Well I hooked my gauge set up, and with the compressor running the low side was 130psi, and high side was around 350psi. So I'm going to assume it's not low on R-134a. So that begs the question...Where can the problem lie? I was thinking it could be in the compressor itself, but then realized it could also be the expansion valve, but then the thought occurred to me that also the condenser coils could be restricted. Any ideas? If all else fails I'll start the process of having the system evacuated and replacing components starting with the expansion valve.

 

Off hand I want to say on the low side it is suppose to be 35-40PSI. Double check in the manual, which you can download in the FAQ just a few posts above this one. There is an entire section on the AC system.

My guess is it is that the fan is not cooling the radiator and the condenser enough. If so the fan clutch may be bad if it is a V6 or V8. If 4cly maybe the electric fan is not working properly or the temp sensor.

 

It's a V-6. I would think if the fan clutch were bad, then it would be overheating while sitting in traffic. But indeed it doesn't get hot at all. The temp gauge just goes to about 1/4 way and stays there after the truck has been running for awhile.

 

make sure you're reading the right gauges. Low side will never go over 130 psi if the compressor is running. Usually low side gauges will go up to 130 and then 350 and have a section saying RETARD. Also, freon is affected by temperature, if you underhood temps are 150 degrees, you'll notice that the gauges will read around that before the vehicle runs.

On that note, from what you describe, it sounds like you have an electrical problem to where you compressor clutch is not engaging. As crazy said, a properly operating A/C system while running should be 35-40 psi on the low side and 175-250 psi on the high side.

Try this: locate the low pressure switch on top of the accumulator (passenger side by firewall) disconnect the sensor and with a paper clip jump the two terminals of the connector. If the compressor engages, you have a bad low pressure switch.

 

I know how to tell if an A/C compressor is running or not. This one is definitely running. And the pressure gauge that I have definitely said 130psi. It is a working pressure gauge, because I used it later that day to check another A/C. So once again, when the temps are below 80 outside the A/C blows nice cold air. Once the outside temps start to climb above 80, that's when the A/C quits blowing cold air.

 

It doesn't have to be over heating for a dead fan clutch or inaccurate air flow. Just yesterday my AC in my Suzuki wasn't working to good and engine temp was just fine. I pooped the hood and the plastic retainers that hold the fan shroud to the radiator broke. The fan shroud jambed into the fan and seized it up. That is why the AC wasn't working that good and no overheating.

 

I'm going to check out the fan clutch. I wanna say it's the original fan clutch that was on there from 1995. If so it has less than 150xxx miles on it, but still that is a lot of mileage for a fan clutch. Don't they lose like 100-150rpm for every year?

 

yust my 2 cent's im gonna say it sounds like it's over filled and the stuff just has no where to go. a properly filled system will not do this ever. if you have a oriface tube plugged your high side will be way up and your low side will be 20 psi or less. i really think your way overfilled.
normally i look for 25 to 30 psi low (depending on the vehicle some as high as 35 you shouldn't go lower because the compressor will shut off when the pressure switch opens. and around 250 high side. both my dakota (charged at work with 2lb per the service info in tech connect) and my caravan (2.4 lbs if i remember right) are in that area and both are cold as ice.
if it was a prob with airflow on the condenser then you would have air at speed but not at red lights (a low system will do that aswell)

 

ouch you pooped the hood?

 

dood that had to hert LMAO. J/k I dont mean to highjack a thread but I do have a question on this topic. I can run my AC in my truck and it will blow ICE cold. but after 5 minutes of running my compressor starts making a wirring noise. could that be the orriface ? or the comp goin bad?