[CTS_Kenny]

I don’t drive Lucille very often, except on weekends and to work from time to time. With only 17k on her I wouldn’t think the compressor would be having issues.
So last summer I had driven her to work a few times, and once or twice I noticed that I had to have the AC on full blast all the way home(50 miles). At the time I didn’t think much of it except that it’s a damn hot summer this year! The other day I was moving around some cars in my driveway and had to pull Lucille out to get my wife’s CTS in the garage. I had pre started 3 CTS‘s and that’s when I noticed how warm it was inside of Lucille. Not HOT but clearly a tad bit cooler than the others. The 2 others were ice cold, and Lucille was sorta blah! Big noticeable difference! Needless to say I was pretty bummed. Said to myself “ I knew it”!! I knew that wasn‘t normal last summer.
So the next day I did some research on what the correct PSI for the H and L sides and what they were supposed to be. Here’s what they were at idle. See pics
I also put them to the test with the thermometer in the vents of Lucille and one other CTS. 58in Lucille and about 54 in my wife’s CTS. Not bad, but not good either. I seen 44 in our cavalier That was while driving of course.
From my understanding, this is pretty good numbers considering the temp was about 93 and about average humidity. Pretty humid here in Texas.
I guess my question is, what to do from here? Although I had some recent success with some stop leak on our Cavalier, I sure have some hesitation about putting anything other than refrigerant in Lucille. My first thought is to pull all of it out of the system and recharge it to the correct amount. NO WAY am I just going to start adding refrigerant and possibly really screw things up. Any knowledgable AC guys have any ideas on this situation?

 

[Sudderth]

I end up adding a can of refrigerant every year or so. Sometimes, just a half can. Interesting how sensitive how this car is to being low on R-134. The passenger side will get hotter than the driver's side if it starts getting low on refrigerant. Also, the computer controls the fans and the fan speed. I replaced the fan relays this year since the car refused to run the radiator fans on high speed. They worked but not on high. And, at an idle the car was producing musty and not too cool air. Anything above 35 miles an hour and the fans are not required. So, I would think yours is just a little low on refrigerant since, at speed the car does not cool properly. I do miss Texas with the humid air. Makes the air conditioner perform better than here in Las Vegas. Too hot and dry and altitude to boot.

 

[Blades1_99]

I end up adding a can of refrigerant every year or so. Sometimes, just a half can. Interesting how sensitive how this car is to being low on R-134. The passenger side will get hotter than the driver's side if it starts getting low on refrigerant. Also, the computer controls the fans and the fan speed. I replaced the fan relays this year since the car refused to run the radiator fans on high speed. They worked but not on high. And, at an idle the car was producing musty and not too cool air. Anything above 35 miles an hour and the fans are not required. So, I would think yours is just a little low on refrigerant since, at speed the car does not cool properly. I do miss Texas with the humid air. Makes the air conditioner perform better than here in Las Vegas. Too hot and dry and altitude to boot.

Oddly, I was just thinking about adding but I don't know what the pressures are, because it feels just "okay".

 

[RobF300]

i remember my G8 being short filled from the factory on refrigerant and what a difference having the shop top it off made

 

[Sudderth]

Topping it off with a little under a can of R-134 should be all you need. You will know if you have too much since the temperature increases if you have too much refrigerant. I think the high side ought to be about 250 and the low side ought to be around 45. So, your system is close. Other interesting thing... Have you changed the cabin filter. Run the system on recycle so it bypasses the cabin filter.

 

[djdonte]

Was the compressor cycling when you took these pictures? The low side looks a little low and the high side looks very low. I think you are just a bit low on freon for a 90-95 degree ambient temp. Get a bottle of R134a and a tap and add a bit while monitoring pressures as well as air vent temperature. Just put a little at a time. This chart should help. The way the snap on AC machine works is they charge until the vent temperature stops going down and goes up, then it sucks a little back out. I cant condone venting freon to the atmosphere tho.

If you need topping off again soon, you need to find the leak or add stop leak. I've seen the stop leak work for super small leaks, but I would only use it for a beater. AC stop leak doesnt stop crack leaks like radiator stop leak, it just makes the o-rings swell. On a V I would locate the leak with a sniffer or dye and fix it.
R-134a System Pressure Chart - AC Pro (acprocold.com)

 

[RocketSled]

The AC condenser is located in front of the engine radiator. Check to make sure there's nothing blocking airflow, especially between the two radiators. My 02 Z06 used to suck up shit like a Hoover Upright as it drove down the road. Every spring, part of my regular maintenance, I'd blow out the space between the two with compressed air (long "wand" so I could reach all the way up) and get a face full of sand and plant matter for my trouble, and sometimes a cigarette butt or two.

 

[kittyboy]

These days professional mobile AC services are available for home scheduling, I use such a service. I'd replace AC system O-rings, condenser, and desiccant bag prior to a scheduled appointment. The benefits to having a professional service are proper vacuum testing to insuring no leaks exist in the system, circulating the coolant and filtering out moisture, insuring a correct amount of coolant and compressor oil is added back into the system. I think it cost me $175 for the service in 2021 and took about an hour. I also had dye added to the coolant to assist with locating potential leaks in the future. It's well worth the time/money investment.

In my case system components were inspected and replaced prior the actual service call visit, your situation is different. If you have the ability, a good standard is to replace the components I noted, not expensive, just a little pain. It's not as involved annually after you've properly serviced the system once with a good go-over. The desiccant bag should be replaced annually in my opinion.

 

[djdonte]

These days professional mobile AC services are available for home scheduling, I use such a service. I replace AC system O-rings, condenser, and desiccant bag prior to scheduled appointment. The benefits to having a professional service is proper vacuum test insuring no leaks exist in the system, circulating and filtering out moisture, and insuring a proper amount of coolant and compressor oil is added back into the system. I think it cost me $175 for the service and took about an hour. I also had dye added to assist with locating potential leaks in the future. It's well worth the time/money investment.

I realize that in my case system components were inspected and replaced prior the actual service call visit, your situation is different. If you have the ability, a good standard is to replace the components I noted, not expensive, just a little pain. It's not as involved annually after you've properly serviced the system once with a good go-over. The desiccant bag should be replaced annually in my opinion.

If he has a manifold all he needs now is a vacuum which autozone usually rents. The desiccant bag only needs to be replaced when the system is opened. Opening a sealed refrigerant system just to replace the dryer is a waste of Freon, O rings and labor.

 

[kittyboy]

Yeah, I know it's overkill, but if the system is having issues and it's been awhile just thought it might be a consideration to insure overall.

 

[CTS_Kenny]

I end up adding a can of refrigerant every year or so. Sometimes, just a half can. Interesting how sensitive how this car is to being low on R-134. The passenger side will get hotter than the driver's side if it starts getting low on refrigerant. Also, the computer controls the fans and the fan speed. I replaced the fan relays this year since the car refused to run the radiator fans on high speed. They worked but not on high. And, at an idle the car was producing musty and not too cool air. Anything above 35 miles an hour and the fans are not required. So, I would think yours is just a little low on refrigerant since, at speed the car does not cool properly. I do miss Texas with the humid air. Makes the air conditioner perform better than here in Las Vegas. Too hot and dry and altitude to boot.

Not sure if a pro AC guy would recommend just adding R134 unless you‘re 100% sure you have a small leak. Seems a bit dangerous bc of possible overfilling.
I was beliveing you until you said you missed the humid air in Texas. I know now you are a bit delusional Haha! That dessert air has gotten to ya bro 😂. F this hot humid shit! 54 years here and I still can’t get used to it.

 

[CTS_Kenny]

The AC condenser is located in front of the engine radiator. Check to make sure there's nothing blocking airflow, especially between the two radiators. My 02 Z06 used to suck up shit like a Hoover Upright as it drove down the road. Every spring, part of my regular maintenance, I'd blow out the space between the two with compressed air (long "wand" so I could reach all the way up) and get a face full of sand and plant matter for my trouble, and sometimes a cigarette butt or two.

You might be onto something there Rocket. The guys here gave me shit when I zipped tied the license plate to the front lower grille. Maybe that could block just enough air to stumble it a bit.
Took Lucille out yesterday and seemed to work great! True it was only 80 out, but very humid, and felt very COLD. Wish I’d have brought the thermometer with me.

 

[CTS_Kenny]

Was the compressor cycling when you took these pictures? The low side looks a little low and the high side looks very low. I think you are just a bit low on freon for a 90-95 degree ambient temp. Get a bottle of R134a and a tap and add a bit while monitoring pressures as well as air vent temperature. Just put a little at a time. This chart should help. The way the snap on AC machine works is they charge until the vent temperature stops going down and goes up, then it sucks a little back out. I cant condone venting freon to the atmosphere tho.

If you need topping off again soon, you need to find the leak or add stop leak. I've seen the stop leak work for super small leaks, but I would only use it for a beater. AC stop leak doesnt stop crack leaks like radiator stop leak, it just makes the o-rings swell. On a V I would locate the leak with a sniffer or dye and fix it.
R-134a System Pressure Chart - AC Pro (acprocold.com)

Yes it was in HIGH. According the little research I did, those are pretty good numbers considering the conditions out the other day.
Also, if there was a leak, after so long, don’t you think it wouldn’t get cold at all? Like I had said, last summer driving my 50 mile trio home from work, it stayed on full blast the whole trip home. My 14 year old truck at the time I would get 5 miles on my trip and lower the fan speed bc it was too darn cold. Same with the 02 Cavalier. I knew something wasn’t right but figured it was extra hot or something that day. Then, moving the cars around last weekend I noticed that big difference again.

 

[djdonte]

Yes it was in HIGH. According the little research I did, those are pretty good numbers considering the conditions out the other day.
Also, if there was a leak, after so long, don’t you think it wouldn’t get cold at all? Like I had said, last summer driving my 50 mile trio home from work, it stayed on full blast the whole trip home. My 14 year old truck at the time I would get 5 miles on my trip and lower the fan speed bc it was too darn cold. Same with the 02 Cavalier. I knew something wasn’t right but figured it was extra hot or something that day. Then, moving the cars around last weekend I noticed that big difference again.

Just because it was on HIGH doesnt mean the compressor was going. It turns on and off. You have to look at the compressor clutch to see if its moving or just free spinning. There is a low pressure switch that will cut it off too. If it is constantly turning on and off that a classic sign of low refrigerant. For 93 degree ambient, the pictures you posted look low. Not super low, which explains it only slightly cooling. And yes if there is a leak it would eventually stop working due to the low pressure switch. This is pretty common with older cars, I would shoot just a LITTLE 134a and see if it helps.

 

[RobF300]

i find much cooler air if i run the fan a bit slower, and it sounds dumb but are you sure the temp setting is at 60 or LO? ( i actually forget which the V displays lol )

 

[djdonte]

i find much cooler air if i run the fan a bit slower, and it sounds dumb but are you sure the temp setting is at 60 or LO? ( i actually forget which the V displays lol )

If thats happening then I would bet you are a tad low on freon too.. The evap coil should be able to handle it unless you are pulling in 100 degree air from outside. Does it do that on recirculate too?

 

[RobF300]

If thats happening then I would bet you are a tad low on freon too.. The evap coil should be able to handle it unless you are pulling in 100 degree air from outside. Does it do that on recirculate too?

im saying in any air conditioning meaning home, car, the air seems to have more time to cool if the fan is a little lower. I know getting into a hot car you want that air on blast to get things moving but once cruising along the air just feels colder when the fan is slower especially in humid climates. Slower moving air dries better

 

[CTS_Kenny]

Just because it was on HIGH doesnt mean the compressor was going. It turns on and off. You have to look at the compressor clutch to see if its moving or just free spinning. There is a low pressure switch that will cut it off too. If it is constantly turning on and off that a classic sign of low refrigerant. For 93 degree ambient, the pictures you posted look low. Not super low, which explains it only slightly cooling. And yes if there is a leak it would eventually stop working due to the low pressure switch. This is pretty common with older cars, I would shoot just a LITTLE 134a and see if it helps.

If I remember yes it was on the short time I flash lighted it a couple of times. I didn’t hear it turning on and off I’ll say that, so I assumed it stayed on. Not 100% sure tho.
I like your earlier idea of slowly adding some refrigerant until the temp gets to the right degree tho. I might do that if I continue having up and down cooling. Also, I’ll take another close look and check everything out a bit closer.
Tell ya what, today is one hot ass humid day, so it might be the day to check it out.

 

[djdonte]

I would not add until it’s cold tho unless your positive the Freon is low. I was just giving an example on how the pros do it if they’re not using a scale for a new charge. If the problem is elsewhere too much will be bad as well. I would just shoot a little in there while it’s running on high. If the vents immediately get colder then add more until you get pressures that correspond with the chart I linked you to earlier. A cooking thermometer in the vent is best but your hand will work too.

 

[CTS_Kenny]

I would not add until it’s cold tho unless your positive the Freon is low. I was just giving an example on how the pros do it if they’re not using a scale for a new charge. If the problem is elsewhere too much will be bad as well. I would just shoot a little in there while it’s running on high. If the vents immediately get colder then add more until you get pressures that correspond with the chart I linked you to earlier. A cooking thermometer in the vent is best but your hand will work too.

Yes, understood. I usually use the cooking thermometer. they seem to work well. I gotcha tho. Thx