Summer before last I had a shop replace the compressorr, orffice tube and something else pertinent to the ac system and re charge it on my 97 psd. It blows cool, but not cokd. Compressor engages, but the canister thing under the hood doesn't get cold and frost over like normal. Any idea on what could cause this. I was going to try recharging it, but the gauge I was using shows it has a good charge.

 

You have air in the system, the only way to do it right is getting all the old freeon out vaccum the system and add accordingly.

 

 

Buy a real gauge set. Yellow Jacket or Mastercool.

You may as well reseal the system if it is that low on charge. All orings then recharge. I think mine spec'd 38oz. I was too lazy to pull out my 134A tank and shot in three, 12oz cans. 94.7% charged, say I lose a hair from venting the air... I am 91% full and put out low 40s from the vents at high idle.

Hopefully the system was flushed and a new condenser installed too. All components are so inexpensive, it is silly to not just replace all. The only thing semi expensive are the hoses. You will be shocked how much **** accumulates in the evaporator core over time. Pull the blower and take a look. I spent a few hours cleaning mine, way better air flow and the evap can now pull way more heat from the air.

 

The truck has a adequate charge, no need to re seal or re charge.

 

It leaked out in a few years after replacing major components... that is not normal.

Pick up a refrigerant detector and see where the leak is located.