2005 gmc sierra air condition will not cool

[randall moore]

My air condition has been worked on by local dealership still not working and several air condition professionals. Here are the symptoms and things that have been done. The lines going into the evaporator, one line is cold and one is not. The dryer has been replaced,expansion valve orvis, vacuum has been pulled and the correct amount of refrigerate added. The clutches are running, pressures on the low side and high side are correct. The condenser is not blocked, I know that the dryer should be cold and both lines going into the ,evaporator should be cold. Sometimes both lines going into the evaporator are cold and while running and clutches engaged and pump running the one coming from expansion valve is cold and the other one coming back from the evaporator becomes warm. We blew low pressure air through evap just to check for blockage. All help and advice is greatly appreciated.Thanks in advance

[diyer2]

I think the refrigerant isn't making a complete loop.

[arcasey]

My air condition has been worked on by local dealership still not working and several air condition professionals. Here are the symptoms and things that have been done. The lines going into the evaporator, one line is cold and one is not. The dryer has been replaced,expansion valve orvis, vacuum has been pulled and the correct amount of refrigerate added. The clutches are running, pressures on the low side and high side are correct. The condenser is not blocked, I know that the dryer should be cold and both lines going into the ,evaporator should be cold. Sometimes both lines going into the evaporator are cold and while running and clutches engaged and pump running the one coming from expansion valve is cold and the other one coming back from the evaporator becomes warm. We blew low pressure air through evap just to check for blockage. All help and advice is greatly appreciated.Thanks in advance

 

Does it cool any better while driving/moving or is it not cooling at all?

 

Also, while all of the repair work was being done, did anyone check to see if the Blend Air door/flap was functioning properly?

[randall moore]

yes i do agree that it is not making a complete loop, I think the evaporator is stopped up or contaminated with something. (note; I did blow air through the evaporator just to see if air would flow through, it did) No it does not cool any better while running. Just making sure something else in the circuit that i was missing. Dont have to worry about doors if it is not coming back from evaporator cold.(Note; blocked off heater hoses while trouble shooting) Clutches are engaged and running. Thanks for the comments if anyone knows anything else to try I am desperate. Does anyone know if there is any kind of valve in the line once it goes through the fire wall and into the evap.

[arcasey]

Well, with all that said, it sounds like you are on the right track. You probably have a flow restriction somewhere. Could be that the evaporator does have a small restriction and just not big enough to show up during your low pressure air test. Or there is some moisture in the system that may be freezing and causing the obstruction near the orifice tube, which based on the symptoms you described of both lines going to the evaporator being cold and then once it's been running for a short period of time the evaporator outlet becomes warm is a possibility. I would be surprised since you have pulled a vacuum on the system already.

[randall moore]

Thanks so much for your help, i was thinking the same thing about moisture causing the problem. I changed the dryer hoping it would help. If you or anyone else can come up with anything it is greatly appreciated. Just wondering what could be in the evaporator, just a note; when i changed the orvis expansion valve there was no dirt on the filter. Anyone know how to clean out a evap without taking it out. I have blown air through it.

 

Thanks,

[randall moore]

Just a little update, went to the local dealership to ask the head mechanic a couple of questions. I have noticed that when both lines going to through the fire wall into the evap it cools, when one line becomes warm and the dryer is warm it does not cool inside. I ask the technician if both lines are suppose to be cold and he said no, that one would be cold and the other one warm. I checked two my other vehicles and my neighbors and some of the vehicles one line is cold and one is warm, the other two vehicles both are cold. I am totally confused. He also stated the he has not seen any evaps go bad unless leaking. Can anyone explain why some vehicles both lines are cold and other one is cold and one is warm.

 

Thanks for all the help

[muddkatt]

Can anyone explain why some vehicles both lines are cold and other one is cold and one is warm.

 

Thanks for all the help

It depends on where the expansion valve is located in the system. Different makes, models and years cant be used as a reference for your vehicle.

 

What year truck do you have?

[randall moore]

2005 GMC Sierra

[muddkatt]

2005 GMC Sierra

Sorry, I see its in the title...I should refrain from posting until the 3rd cup of coffee.

 

I just looked up the parts at Rockauto and there is nothing in the evaporator that would cause a problem unless it is leaking, or clogged up EXTERNALLY. In other words, no airflow across the coils.

Have you checked the cabin air filter? They show one available.

[randall moore]

I have not checked the cabin filter, cold air blows out when both lines going to the evap are cold, then one line becomes warm and it stops cooling but still blowing air.

[arcasey]

I have not checked the cabin filter, cold air blows out when both lines going to the evap are cold, then one line becomes warm and it stops cooling but still blowing air.

 

You likely do not have any issues with the cabin air filter then, but that doesn't mean it doesn't need to be replaced. My mom had a 2004 Yukon XL that we could not figure out why it would not blow cold air. Had the system worked on numerous times and no fix. Finally, someone suggested the cabin air filter and we changed it and everything was working again. I will say that if the cabin air filter is causing that much of an issue you should notice a difference in the amount of air flow through your vents because there would be some flow restriction.