Automotive Air Conditioning Information Forum

I have a 2004 GMC Sierra.

The air works great driving or in park running.

However when I am at a red light in gear (Lower RPM) the air is warm.

When I accelerate it gets cooler again.

I put a new flan clutch in and no improvement.

Could this be a possible orifice tube issue?

Thanks,
Lee

That 18 yo vehicle is most likely low on charge, since you already installed a new fan clutch (they are only good for 2-3 years anyway). Insufficient refrigerant is the most common reason for poor performance. There are losses due to attrition thru the hoses, etc.

Strongly advise that you have an AC shop (not a brake and muffler place) recover what is in there, and charge by weight to the correct spec. Then go from there if needed. We are assuming that the comp has never grenaded.

Are you the original owner of this truck, and do you know whether the A/C system has ever been serviced? Does it have rear A/C?