I noticed a few days ago while driving on the freeway that my Ac temps would fluctuate. So today I got a meat thermometer and stuck it to the middle bent. First temp it hit idling was about 50 deg. Then few min later it went up to 60. Drove it, put ac on max and it remained about 54deg. Then all of a sudden w. Then it went down to about 46, then up again to 58. Parked, put it on low (1) temp went down to 38, then up to 58. In taking it to check it, but wanted some feedback if anyone has experienced something similar. I've read it may need to be charged, or it may even be overcharged that can cause this. Thanks!

 

Just had an issue with my ac this summer, I have done my own ac maintance for years and here is what i do know, IF they system is good and just needs a recharge the compressor will cycle on and off rapidly, once charged the compressor should stay engaged for awhile and only cycle off and on when needed. Also if the system is low on freon, its typical that sitting at idle the ac will be pretty cool like it should but the faster you idle up the engine or take it up to highway speed the air will increase in temp. When you come to a stop and wait a few like at a light the air will get colder. And on my 6.4 it was almost impossible to tell what the compressor was doing over the noise of the engine so i had to actually put my hand on the low pressure side pipe and use the sense of touch to tell what the compressor was doing. I did find I had a small leak, but heck its an 2008 not really surprised, so I used some stop leak with leak finder and oring conditioner along with recharging the system and so far no issues. I am putting out 38-40 degree air all the time now. I wish you luck.

 

Thanks for the reply. It's at the shop getting pressure tested. It's a 2010, bought it used so who knows the history of the AC maintanence. Hopefully it just needs to be recharged.

 

Please let us know what you find out.

 

Got it back, mechanic told me pressures were off and it needed some freon. Unfortunately, 20 min later after picking it up temps went from 48/50deg to about 62. Outside temp was at 98 deg. He asked for me to bring it back, so it's back with him. We will see what he says again.

 

Fixed! It was the clutch gap. Said it was too open. Tested it for 15 min, temps between 42-50 constant. Dropped to 40 on idle set at "3" on fan speed. Hopefully no more fluctuations! Current outside temp is 96 deg here in TX.