Charging the air conditioner

Air Conditioning problem
2006 Kia Sedona 6 cyl Two Wheel Drive Automatic 68000 miles

We have had this vehicle since new and not nad this problem before now. In May, we had the 65K service (replaced timing belt.) In June after the outside temps got hot, the A/C compresssor had a complete failure which sent debris throughout the system. 1600$ later at dealer, we have a new AC and flushed lines.

After several weeks to a month, the A/C failed again and they replaced the copmpressor. A few weeks later, it failed again and they replaced the entire system and cabin switches. Last weekend, It started to act up and smoke, I immediately turned the car off and restarted the vehicle with the hood up to watch for trouble. The A/C ran fine all the way home and appears to be fine now.

At each failure, it was durring the heat of the day (above 105 degrees F outside). The car had been sitting outside for at least a few hours when at startup the AC failed/ or acted up.

My initial questions are: Are there any ancillary connections to the A/C system that could be causing this repeated failure? Is it possible that the 65K service is related to this failure (overtight belt.)?

I appreciate any input or advice regarding this question as I am concerned that if we don't get it resolved before the temps drop, I will be out of warranty when it failes next.

Thanks,

Don

Where do I charge my freon on my 2005 Kia Sedona? I am not seeing the valve shown on the instructions when looking under the hood. Thanks.

I would like to know what the low pressure side readings/specs should be when the A/C is on and when it is off. Cooling seem a bit weak & the compressor is cycling on/off more than I think it should. I have one of those consumer type trigger guages that show it in the "blue" (full charge) about 40PSi on & 105psi off. Did not check high sige as I dont think this guage is meant for that. I also note ther is a distinct hum when the A/c is turned on. If its low I plan on adding some of the synth stuff that has some oil & super cooler in it.