I was answering only the question at hand. There are other thinks to check in diag on the A/C. I think I answered his question, and am not going to go round and round with other sinarios.

 

THANKS EVERYONE!! CAN' T WE ALL JUST GET ALONG?? CHEERS!

Several different approaches were great!

 

Of course we can. Like I said, everyone is entitled to there own opinion and I am just really curious how some of there conclusions were found. Someone else's idea or opinion could make something easier. I also go by another saying other than the one in my signature. The day you know everything about your job, it's time for a new career. You can learn something new everyday, because things change everyday. The day you know it all, is the day you decide to quite learning. We're all fellow Mopar owners, here to help and chat with others. To me there are no hard feelings. I hope that even with our disputes, at least in the long run, your problem is solved.

 

Thanks for all the great info! Is there any advantage in wrapping the ac lines with a Thermo-tec product? I know my cold lines sweat a bunch and other ac systems sometimes wrap or insulate their lines from ambient heat. So, I was wondering whether wrapping the lines, protecting them from engine heat, would do any good? Thanks.

TazKing
2003 Durango SLT

 

I read in here a while back about rapping the lines. They do this to durangos in like Arizona, where triple digit
temperatures are common.

 

And by the way. This statement is so wrong!

I frozen evaporator will not work, and the a/c would blow warm air..... The evaporators job is to transfer the heat in the air passing through it to the freon flowing through the lines. THats how the air is cooled. It is removed from the air by the evaporator. If it was frozen, It would not transfer the heat out of the air efficiently to get the air cool.

 

To add further details on this. Digitoxin is right about heat transfer. But the evaporator coil must be designed to have a maximum heat transfer at the highest setting. Then naturally at lower speeds, the coil is over efficient in removing the heat, thus giving you the feel of colder air coming out at lower speeds vs higher speeds. But if the coil is way too over efficient, then cooling off the air too fast at lower speeds will eventually freeze up the coil and thus, no air flow or very poor air flow and not much heat transfer. So there needs to be a balance when designing an A/C system which uses variable fan speeds. Pressure safety switches are put in place to disconnect power to compressor to prevent the coil from freezing if there is not enough air blowing thru the coil to maximize heat transfer and prevent freeze buildup.

Also, you will notice when the engine is at idle rpm, the A/C is not as cool as when the engine is running at optimum rpm speeds when on the highway. This all relates back to heat transfer again from the compressor being able to pump out the heat. The optimum rpm speeds for the A/C compressor is anywhere from 1500-2500 RPM's to operate at maximum designed efficiency. If the compressor falls out of this range, pressure safety switches are put in place to disconnect power to the compressor to protect from damage.

Now you can wonder why alot of A/C's goes out in alot of cars so early when the car is still relatively new. I guess it is mainly because alot of owners are hard on their engines when driving and excessively exceed the RPM range of the compressor. The most common failure due to hard excessive driving with A/C running is freon leaks.