2007 Yukon Denali XL A/C cutting out int

[Rayaz_XL]

The vehicle has 163,000km on it. The problem is the A/C is not as cold as it was. More so when I am driving, i notice all of a sudden warm outside air being blown through the vents instead if A/C. Intermittently, the A/C kicks in but very moderatly, even though the temp is set down all the way, and it is not on AUTO. Even on recirc mode the A/C is not as cold as should be, and cuts on and off especially when driving.

 

Any comments, advice, opinions, experiences, etc appreciated. Thank you.

[Robert1]

Maybe kicking out on low pressure switch. I'd have the charge checked on it.

[Rayaz_XL]

Thank you, I will bring the truck in for a A/C Charge and check. Do you know causes the A/C to kick out on low pressure switch?

[Robert1]

Thank you, I will bring the truck in for a A/C Charge and check. Do you know causes the A/C to kick out on low pressure switch?

 

 

Auto hvac systems unlike most home a/c systems unitlize several compresion fittings on the lines and expansion valves.Over time they have a tendancy to develop small leaks of the refrigerant charge. Since the compressor is cooled by the refrigerant it pumps,manufacturers incorporate suction side/low side pressure switches that will detect a low pressure situation and de-energize the magnetic clutch. Of course once the compressor shuts off,this low side pressure begins to rise as the high and low side pressure of the system balances back out,thus raising the low side pressure which re-energizes the magnetic clutch and causing the unit to short cycle. Over time this will reek havoc on the compressor clutch. Have a reputable shop check and adjust charge and locate and repair leak if it is significant enough to detect.Many times there will be an oil residue present near where the leak source is at,but not always. It depends on the volume of the leak. Good luck.

[Rayaz_XL]

Wow you have totally opened up my mind, clear and made me totally understand whats happening now. Thanks so much for your insight!! I see oil residue present around the high press line fill valve. I hope it may only be a lose schrader valve!!!

 

What I did was basically a cheap temporary fix, because i have two babies under the age of two in the vehicle that should be cool and comfortable. I tried out a product called Duracool. It states it works best if you have 35-40% R-134a in the system. My system was around 40-50% full. I topped up the system with the Duracool product and it is Ice cold! On a very humid day there is frost blowing out of the vents occasionaly when set all the way LOW.