OK. I've read through as many threads and stickies as I can find, but still can't find the answer. My a/c isn't cooling like it should. I had the compressor and drier replaced about two years ago and the system never has cooled like it should since the work.

Yesterday afternoon, I checked the pressures with the ambient temp about 85. Vent temp was like 65 degrees F, low side pressure was about 40 psi and the high side pressure was approximately 250 psi (high?). Depending on what reference I look at, some say the low pressure should be 20 to 30 psi at this temp and guide on the gauge set says like 45 to 55 psi and high side pressures can be anywhere from around 175 to over 300 psi. Anyway, what I did was add a little refrigerant to see if it makes a difference. Low side pressure was raised to about 45 psi and high side went up to 275 psi and vent temp might have dropped two to three degrees, but not much.

Here is the weird thing. Last night after the sun went down, the ambient temp was still 75 to 80 degrees. I check the pressures again. With the engine idle at 1500 rpm, the low side was like 25 psi and the high side 210 psi and the vent temp was 60 degrees F. This doesn't make sense. Why such a huge difference between pressures? The ambient temp had only changed about 10 degrees. (I have run the pressure test before at different times of the day and get the same results.) Anytime on a warm day, the vent temp never drops below 60-65 degrees. But on a cool morning with the ambient temp around 70 degrees, the vent temp will drop to almost 35 degrees. All manuals I can find say the durango should blow air from the vents at a temp around 45 degrees even when the ambient temp is 85.

I did spray the condensor off at the car wash to clean all the bugs and dust, but it didn't seem to help much.

I just don't know what to do next. Could it be the evaporator or expansion valve. I also wonder if when the compressor was replaced, was too much oil put in or maybe the wrong oil. I've got a sanden sd7h15 and read where too much oil or the wrong oil can have a negative effect on performance. I think I'm going to evacuate, pull vacuum and replace refrigerant to see if that will help. I don't want to replace parts unnecessarily, but I'm also tired of riding in a hot vehicle.

Any suggestions would be greatly appreciated. BTW, all the information I've read on this forum has been great.

 

it almost sounds like they didnt put enough refrigerant in the system, the dual system (front and rear) takes 2.44 lbs (which is more than most systems)

 

also i see you didnt say if the expansion valve was replaced when the comp and accumulator was.. it could be clogged from metal particles from the old comp.. always always always change then expansion valve and accumulator if a compressor goes bad, and have the system flushed..

 

I did not have the expansion valve changed. Is it relatively easy to change the expansion valve. I could do this when I evacuate the system. I also know the dual a/c system has two expansion valves, is the rear expansion valve hard to get to. In other words, does the dash have to be removed to replace it? And should I replace the drier again if I replace the expansion valve.

 

i would replace both mine dont have rear ac so i cant tell ya how hard it is or isnt. and i would replace the drier/accumulator . im used to chevy's they have accumulators and orifice tubes instead of expansion valves and driers lol

 

the rear a/c unit is in the panel on the passenger side, by the footwell of the third row seat, the expansion valve should be right in there (i think its attached tot he rear evap core, but dont hold me to it)

 

Give the man a cigar and a scotch! He's correct!

 

Ewwww


What happened to giving a cookie?

 

if he dont want the scotch and cigar ill take it

 

^ lol ^


But ya gotta share!