Thread: AC Performance at Idle

Just curious if this sounds like a reasonable performance for AC. It seems warmer than I remember it while in traffic.

Tested:
-Engine at idle
-Engine at operating temp
-Windows down
-Fan on full blast
-Both temps max cool
-On recirc mode
-Sitting in sun

Ambient temp is 92F.

Center vent gets down to 58F.

All I can say is mine if effing cold. I'll have to take a thermometer for a drive and see what the temps actually are.

Mine is nice and cold while driving, but borderline when stopped for more than a few minutes. I'm just curious if you just sit without driving during a hot day what your temps will be.

When was the last time you cleaned the fins on the radiator and condenser?

It may be worth your time to hose down both of them to get all the junk out of the cooling fins. Last time I did one I just remove the fans to give me all the room to get a hose down there to spray them from behind.

Humidity was roughly 55%. I still feel like it was colder previously, but this is subjective.

Long story short when I first got the vehicle the AC performance wasn't great. I added die and borrowed an electronic detector (can't see inside the dash) and neither turned up a leak. I had a shop evacuate it for me so I could know if it was low, and it was. I have no way of capturing the old freon myself, but I can borrow the tools to charge it. I changed the accumulator, tossed in some fresh oil, vacuumed it down, and recharged to spec. Vac held for over two hours and the pressures were solid once running. This was about 3 years ago. I also blasted out the condenser and radiator at this time. Ran like a champ.

Last year I had borrowed the tools again to work on the other vehicle I have. I tested the pressure on the GP because I had the tools again so might as well. It was on point. But when I removed the tool, the high side blasted out *a ton* of freon for some reason. Cheap Harbor Freight gauge set got caught on the damn fitting as I was releasing it. It was towards the end of the season so it wasn't as hot. I'm thinking this event has me too low now. Should have just left it the hell alone.

Unfortunately I don't have easy access to a place to work on the car now. Considering just saying F it and taking it to a shop and telling them to vac and charge to the proper amount.

But if this is normal performance at idle I would be wasting my money. That's why I'm even debating it.

I also have access to this bad boy, which is the GM system performance test specifications for this car. Another reason why I'm asking is because according to this I'm well within specs.

It honestly just doesn't seem cool at idle even within these specs. I feel like it used to almost freeze me out at idle, but maybe I'm crazy..

https://imgur.com/Nm9l06k
Imgur: The magic of the Internet

Originally Posted by gingerdude

.....but maybe I'm crazy.t

I have this problem. LOL

Have to be a little crazy these days!

So I called up to the shops. I guess if they find it low they won't recharge it until they have determined and fix the leak, which adds another $200 to the price.

Which sucks because I just want to know how much I am low and have it topped off. I know I released a decent amount on accident because that damn fitting got caught during release.

I want to just say "Weigh how much I have in the system and put it back in. I will take it from there."

You can go to the auto parts store and buy a AC recharge can with a gauge if you want.

The current sale at napa has them for $25 for a 14-16oz can with a gauge. It may not be the same price in your state but likely similar. If you want to take the chance and spend a tiny bit of money I'd do that.

It won't tell you the weight of the refrigerant in the system but if it's low the pressure will be down. Typical low side pressure is around 45-50psi. If yours is down around say 30psi then it's down several ounces of R134a.

I took it for a drive this evening with the thermometer in the dash. It bottoms out at 47F in 82F weather with 70% humidity. When stopped it shoots back up to 58F within a few minutes and holds.

I can see the high side pressure on the Torque App. It fluctuates between 190 and 230, but roughly centers around 205 PSI. According to the chart above that is in range.

But still.... 65F air coming out of the vents (which is what the spec calls for according to the images I attached) does not feel all that cool at 90F with 70% humidity. In fact at that temp you can feel the humidity returning to the air coming out of the vents.

I checked the outlet from the evaporator and it was dripping pretty fast, creating a decent puddle under the car. So that's not the problem.

I feel like the chart above was made to prevent warranty AC issues and AC can get much colder than that at proper charge.

I'm thinking of just biting the bullet like you said and grabbing one of those cans. Then I can see both low pressure (on the can) and high pressure (reported by OBD port) and get a much better picture.

Maybe I'll just spray some in and see if the temp drops at all...

Well I found the problem. Got a black light LED flashlight. Found a stream of dye below the fitting that connects the compressor outlet hose to the condenser intake.

When I get a chance I will crack her open and do it right this time. I should have replaced all the seals and valve stems last time I had it open, but oh well now.

Guess I'll get to have fun trying to get to that damn orifice tube below the brake booster too.

I'm in the same boat.. after redoing the whole thing. I got a new leak it the condenser I'll be doing the orfice tube

Sent from my SM-N920V using Tapatalk

I know how that feels. Both vehicles we have have poor AC performance this year.

My other vehicle is a Chevy Aveo. I just redid the Aveo AC last year, full rebuild on that. I did a half ass job on the GP in '16 when I got it.

Ironically the Aveo is leaking in the EXACT same spot as the GP. Outlet hose from the compressor into the condenser at the fitting. Just my luck....

So I get to redo *both* ACs at some point. Yay!

At least with the Aveo it's just one seal and the accumulator. I had to replace the entire condenser because of a poor design where the accumulator becomes seized onto the condenser and it's 50/50 that you can break it free without damaging the condenser. I think you know how lucky I was there... lol

Just an update. I rebuilt my AC a few weeks back...

Blows like a freaking freezer now!