so when it gets hot and the AC doesn't cool like it does on the road I figure maybe it is low on coolant. Would anyone recommend me going to the auto parts store and buying a can of R-134 and a gage and just filling it up if needed or is it better to take it in and professinally doing it for the price.

Pick 2004 Hemi QC with 92,000 Air coos perfectly down the highway?
anyone else bought those cans from walmart or any other part sotre to check and charge the system.

Also is there different types of R-134 or are they all interchangeable?

 

OK....does it not cool when the truck is at idle and not moving?
If that's the case, check that your AC condenser fan is running strongly.
That's the fan behind the small radiator on the drivers side in the engine bay.
When the AC is seelected from the HVAC controls in the cab, this small fan will always be running.
Hope this helps?
Al.

 

You have to check the pressure reading in the system, this is best done by a certified mechanic, You could have a faulty pressure switch either high or low, could be overcharged or undercharged, could have air in the system if it wasn't charged the right way before. You can check the sensors yourself by making a jumper wire and disconnecting the sensors and jumping the 2 sockets together with the wire. Although if the clutch is cycling properly and not to rapidly your sensors are usually fine. Your Compressor could be on it way out as well. There are just way too many problems that it could be without checking it out all we could do is guess. If you are mechanically inclined you could pick up a manifold gauge set and look through a haynes or chiltons manual or another manual like the service manual and see what pressures you should have and go from there. The hoses on the gauge set will only connect 1 way so you cant hook it up wrong. Hope this helps or gives ideas.

Chris