I have a 2001 5.9 Magnum and my a/c has recently gone out. I stopped using it around November because it got cold so I only used the heater, and now that it is starting to get hot again my a/c isn't working. It kind of comes and goes, but the weird thing is that it works fine if I get going above 65 mph but as soon as I drop down to 30 getting off a highway it blows hot air rather than cold. Any help would be appreciated.

 

Sounds like it may not be fully charged with refrigerant. When I experience that symptom, I typically vacuum the system and refill with R-134a. This ensures that all of the air is out of the system and will perform as best possible.

 

Buy a couple cans of R-134 from wallyworld and a refill adaptor and refill it. Works for me every time. If your serious about fixing it, take it somewhere and get it leak tested, fixed, vacuumed and refilled. But that costs bucks. I have a slow leak on mine and I just throw a couple cans of R-134 in every spring and it blows cold all summer. Just depends on how much you want to spend. $20-30 for a couple cans of R-134 or $200-300 (or more) to find/fix the leak.

 

I agree with jkeaton. I had a '97 Grand Cherokee that had an A/C leak, and I just kept topping it off when the weather got hot. Ran the thing like that for over 150,000 miles. Now on my '94 ram 1500, I don't know if it leaks or not, but I just bought it last fall and decided to top the A/C off a few days ago. Works fine right now, but e shall see what we shall see. I would top it off and hope for the best.

 

Awesome! Probably going the r-134 route. Thanks!

 

That's what we are here for, my friend. Good Luck.

 

Mine has similar issues. But think my issue is the clutch. Worth checking it out

 

i have a 2001 1500 4x4. the a/c works fine early in the morning when i first start but then after a few minutes when it gets hot the compressor kicks off and wont come back on till the truck sits up and cools off. i have plenty of freon,replaced liquid line with orifice tube, dryer and pressure switches. still wont work. please help

 

You may have overcharged it. When you filled it up, did you weigh it in or just go based off of pressure?

 

I just went by the specs I think it was about 3 cans