Ok I've spent a large amount of time perusing the forums trying to find an answer to what I have going on. I haven't found anything yet that for sure matches what I have going on. About a year ago my AC compressor went out. I replaced it, the drier, orifice tube and had it Vac'd and charged. At first it worked great. Then slowly the temperatures started rising when using the AC. If I shut the AC off, waited a few minutes then turned back on it would be cool for maybe 10-15 minutes until it started to warm. Anyway the summer ended and I didn't worry about it until now that it's getting hot again. I had the charge checked at a local shop. They said it was good. Don't know the numbers but that's what they said. The compressor turns on with the AC switch but now it just blows warm air pretty much the same as if I used the vent. None of the tubes seem to be getting cold. I checked the engine fan as I don't ever remember hearing it engage and sound like the jet taking off. The fan doesn't wobble and doesn't free wheel when the truck is off. It will turn but stops as soon as I quit turning it by hand. Feels stiff. So I'm not entirely sure if it's that or where to chase down next. The compressor doesn't cycle on and off at idle it just engages and seems to be doing nothing. I do have access to some AC gauges so I can check pressures but what should they be? Is it the engine fan? The truck started to get a little warm, especially the trans when towing hard at slower speeds. The truck is a 2008 2500 6.7L 4x4. Any advice or help would be awesome.

 

So if I understand, AC works good for a while, then the cab starts getting warm?

Could the evaporator be icing up?

 

It was working well for awhile then would warm up, but now it's warm from the get go. Same temp with Ac on or off. The clutch on the compressor is engaging with the switch but I just get warm air.

 

Have you had guages on it when its blowing hot air? It sounds like a blockage to me.

 

I haven't put gauges on it yet. What should the high and low sides read?

 

30-35 on low side and 250-300 on high side should be pretty close