My truck's air conditioner blows cold air for 3-5 minutes and then goes warm. This is very consistent and happens whenever I turn on the A/C. Then maybe 15-20 minutes later it'll blow cold air again.

Because the problem is consistent I'm thinking it's low on refridgerant. I can only assume that the A/C system is has not been modified. I've only had this truck for a few weeks but I am told the A/C has been this way for a few years.

I'm not in a hurry to get this fixed, with winter approaching, but nobody rides in south Louisiana come summer without the A/C in top notch condition.

 

Hi LSUfan71,

Welcome to the Chevy Forums.

In the spring, have the A/C system charged, being sure that they add leak detector dye. If or when your system leaks again, the dye will expose the leak.

 

Ok, thanks. Would you know if this truck used R-12? Would it need some kind of conversion to a new refridgerant? Or was Chevrolet using the new stuff by 1990? I don't know anything about that.

 

The cutoff year for the ban on R12 went into effect in 1995. GM changed to the new R134 systems in 1994. To the best of my knowledge, more would need to be changed on the system than just the refrigerant, for the system to work at full efficiency.

You should be reimbursed for any recovered R12. Apparently it's valuable. A licensed dealer needs to evacuate what's left from your system to a recovery tank.

 

Check The Pressure For Sure. You Also Need to Check And clean you condenser.

 

Ok, thanks guys.

 

You have moisture in your system. The moisture is whats freezing and blocking the flow of refrigerant at which time the high pressure switch shuts down the compressor, then the moisture thaws out and flows again until it freezes once again. The cycle repeats its self until the problem is fixed.

 

Ok, so I suppose this is something simple to fix for an A/C guy. I'm fearing some type of refridgerant conversion thing costing several hundred dollars.

 

Hello, My name is Mr. O. Jones. I have a 1998 Silverado Ext. cab. The A/C will only take one can of Freon. The unit will not get cold. I was told that I had a restricted system. I flushed the evaporator and the condenser with the recommended flush,Put in a new orifice, new drier. I still have high pressure, about 45. Still won't take but one can. I vacuum the system each time. Still not cooling. What's wrong?