rcchevrolet

I have recently noticed that the a/c compressor is turning on and off too often. I notice this at the first start when it doesn't blow cold air as promptly as before.
Waiting at a light or slow driving in a parking lot looking for a space to park, it is noticeable how the vents don't blow cold air for a moment and then it will blow cold air. On the highway, it's very cold.
Placing a pencil thermometer in the a/c vent at full blast with recirculating air selected the coldest is 60 degrees F. I remember a year ago, in summer, it would go down to about 50-55F.

oilcanhenry

You need to check your A/C pressures. Might have a small leak somewhere. Add some leak detector to the low side port while the A/C is on.. Your A/C pressures should be at 30-40 PSI on the low-side and 170-185 on the high side. It should be blowing at 45 F or less, not 50-55 at 50 MPH or more. 60 degrees is an unacceptable temperature. You may have air in the system. Wear eye protection. Make sure the condenser is clean in the front of your Chevy vehicle.

ruley73

What year is your Equinox?

rcchevrolet

My Equinox is the model year 2008 LTZ 3.4 L AWD.

rcchevrolet

Condenser is very clean, low side pressure is about 35 PSI (reading from DIY container gauge). Thinking of getting an a/c manifold gauge set but don't know how useful it would be to me considering my lack of knowledge, even though I could learn.
Thank you so much for your replies. Any further advise or comments are greatly appreciated.

ruley73

It's normal for this vehicle's A/C compressor to cycle on/off. The colder the ambient temperature is, the more frequently it will cycle if it's running properly. The system monitors the A/C evaporator temperature and cycles the compressor accordingly to prevent it from freezing up. Most newer vehicles are equipped with variable displacement compressors that don't need to be cycled so this is largely a thing of the past.

I would check your cabin air filter and make sure it's not too dirty. Replace it if necessary. Then, make sure both radiator cooling fans are running when the A/C is turned on. No fans means no air flow through the condenser. This yields subpar A/C performance while stopped. The resulting elevated high side refrigerant pressure can pop the relief valve in the compressor or damage other A/C system components if neglected for too long.

The connectors for the radiator fan motors commonly go bad on the 2005-2009 Equinox/Torrent. They develop a weak connection over time which increases resistance and creates excessive heat. If the condition gets bad enough, the fans won't run and the connectors will need to be replaced because they literally burn up. If you need to replace the connectors, be sure to only use connectors made by reputable brands like AC Delco (OEM), Standard Motor Products, or Wells/WVE. The wires on cheaper ones are usually too small for the large electrical load they will be subjected to.

rcchevrolet

ruley73:
Wow, that's a lot of great information. I really appreciate it since that cycling on and off really threw me off. Cycling has a rhythm that begins with the gauge's needle (of the DIY refill gas bottle) in the green zone (approx.35 PSI) and in a few moments moves higher slightly into the yellow zone which then turns the compressor off and repeats. Thinking this meant overcharging I released a tiny amount of gas and cycling is entirely in the green zone.
Very grateful, thank you.

oilcanhenry

35 PSI is pretty normal for the low-side, but you really need to check for a leak. If you use a gauge set, and you decide to add some R-134A, it goes into the low side of the compressor (might have a blue cap on it, but might be black.) You'll need to have the engine and compressor on A/C.on the dash running. The low-side hoses and tubes will be larger then the high-side, but high and low are different fittings so you cant mismatch them, rcchevrolet.

And like I said wear eye protection, and maybe some gloves. Years ago when I was in Junior college learning about A/C and other automotive systems, a girl working on an A/C system (yeah, a girl) did something wrong had the system blow up in her face. She was lucky she didn't lose an eye, but she got shrapnel on her face. Sounded like a bomb going off, but I wasn't near there in the auto shop, so I dont know what happened exactly, but she likely over-pressurized something. She wasn't wear any goggles/glasses.

rcchevrolet

The A/C worked fine on a short trip of 2.5 miles, vent temp 50F but coming back it wasn't cooling much vent temp 60F and noticed something new, the recirculating light turned off and the exterior air intake light went on.
1-Both radiator fans are working fine.
2-The Cabin air filter is very clean.
Looked for leaks in the obvious places like the connection to the evaporator, and connection to the condenser, but found nothing.
Guess I will have to visit a "professional" and see what they say. If only I could trust them here in the big city of Miami, FL.
Very grateful for all the advice, learned a lot.

ruley73

Well, the vehicle is at least 15 years old. It's perfectly normal to gradually lose a small amount of refrigerant, but it adds up over a long period of time. If the AC system has never been serviced, it could just need be recharged.

FWIW we had our 2007 Equinox professionally evacuated and recharged about 2 years ago. We've owned it since 2008 so I'm sure it had never been serviced prior to that. It was about 9 ounces low on refrigerant, and the system holds 1.3 lbs. Your 2008 holds the same amount, so it could definitely be low just like ours was. Ours was behaving similarly before it was recharged. It works pretty good now. It still doesn't seem quite as good as new even though the measured temp at the vents is around 38-40°F. The condenser is pretty beat up from road debris hitting it over the years so I've just chalked it up to that. It's not leaking, but the cooling fins aren't very straight on the bottom 1/3 or so. I simply need to take the time to straighten them out.