Air conditioner not very good or something wrong?

Hi everyone. I have a 2009 Pontiac Vibe GT with 190k on the clock. I recently had the AC compressor replaced and charged up. My mechanic said it wasn’t very cold and he didn’t know why-maybe the cabin filter, which I replaced. I didn’t think much of it since it was 78 outside that day, but he was right. When it’s in the mid 90’s outside, it blows around 48-50 degrees while driving and 50-55 degrees at idle. This is with recirculate on and the the fan on medium high. I decided to evacuate and recharge it myself just to be sure and it’s just about the same still. The max charge for it is 16.46 oz and I have exactly 16.09 in there. Strangely, the thermometer dropped to 40 degrees during the charge after I had only one can (12 oz) in there. I proceeded to add the rest and it is performing no better or worse than before. It also cools much better when it’s below 90 degrees outside and the sun is setting, but above that it’s just not cutting it. Any ideas? A sweaty thanks in advance,

First thing is to verify the temperature blend door is going to full cold position.

Second thing is system pressures, both high and low, at idle and at 2000 rpm.

Third is verify cooling fans operation is good.

These may not be able to be checked by a DIY without the proper equipment.

Thanks.That’s one thing I haven’t thought of-the blend doors. One of the vents is significantly warmer than the others, and one barely any air comes out, so I have it closed. Pressures look normal at idle-I didn’t/couldn’t check at 2000 rpm, fans are good too the best of my knowledge-they work at two different speeds that I have seen. How do I check the blend doors?

Not sure on the blend doors, but when I open the glove box, I can see gears turning for the different vents and temp control.

its possible a vent hose disconnected on the vent that does not blow any air out of.

That seems likely. However, I’m measuring the temp at one of the center vents and plenty of air is coming out. It’s just not cold enough.

Does it have “dual climate control” where you can set different temps for each side (passenger and driver side)? If so, one blend door actuator could be flaky.

Also, if the vents are colder towards the passenger side and progressively warmer towards the driver side (with no dual climate control), that indicates a low Freon charge. Been through that with my Lesabre. I couldn’t for the life of me figure out why my wife thought the AC was decently cold until I stuck my hand in front of that far right (passenger) vent. It was cold, then they were progressively warmer as you went towards the driver side checking vent temps. The far left felt like just the fan with no AC.

What are the pressures, and at what temperature?

why did you have to add more? Could there be a leak still? you should not have to add more after just getting it fixed and charged.

Compressor was shot and needed to be replaced.

update I rarely drive on the interstate, but I did this afternoon for about 4 miles and the temperature at the vent dropped to 37/38 degrees. I thought maybe it was because we had a thunderstorm and the outside temperature dropped drastically, but later the vents crept back up to about 52 degrees while sitting in a parking lot. It seems like I have to be moving fast for the AC to work, and when I do it’s cooooold.

I found this it might help…

Yet another cause of AC blows cold then warm

If your car AC blows cold air when driving at highway speeds but turns warm at stop lights or when driving at slow speeds, you may have a bad radiator fan or radiator fan relay. Many cars are equipped with two radiator fans, while others have one fan that can run at different speeds. In cars with dual fans, one fan is designed to run at full speed any time the AC is on. If that fan isn’t working properly, it can’t cool the condenser enough to remove enough heat from the gaseous refrigerant to get it to condense back into a liquid. That also causes high pressures that can shut off the compressor. The fix? Check the radiator fans to make sure at least one fan turns one when the AC is switched on.

However, some cars operate both fans at low speed while driving and switch into high speed mode when the AC is running. So get tricked into thinking your fans are ok simply because they’re running. They must run at high speed in order to draw enough air across the condenser to make the system cool properly.

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I think you’re on to something. Both fans are spinning whenever I check them, but I have no way to tell how fast or how fast they should be. If that’s the problem, do fans just get weaker over time or is there probably a fuse/relay/electrical problem? Maybe it only spins at low speed?

all things fail as they get older. especially me.LOL
i am not a professional mechanic but I believe the electric fans have a fan control module built into the fan assembly that controls the fans speed. but I could be wrong. I am sure others will respond with the correct answer to that. good luck.

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It is normal for the A/C to perform better while moving than at idle, the compressor is rotating at more than adequate speed while on the highway and there is much better airflow through the condenser.

52 degrees at idle is normal in my area with temperatures above 100 degrees.

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A 15 degree swing between idling and driving on the interstate seems pretty wild, but you’re probably right. I’m a delivery driver, so I’m always making short trips when it’s 95 and over 50% humidity outside. I’m still going to clean the condenser and keep trying to make small improvements. I’m just glad it’s properly charged and works at all :slight_smile:

The unknown to me is what the system pressures are both at idle and elevated RPMs. That question was asked several times with no answer given.

It gets plenty hot here in OK and unless the outlet air is around 40 or below it’s going to be uncomfortable; especially with the humidity.
As for charging, I go by pressures rather than quantity.

I didn’t/couldn’t check the pressure at 2000 RPM. At idle the low side was about 35 and high side was around 150 but I’m not sure. This was at 95 degrees outside. I added 16.09 oz of refrigerant and the maximum amount is 16.46 oz. I have the pretty much the same results as when my mechanic charged it, after which I tried to add just a little more r134a it would shut off/overcharged. I’ll check the pressures again and report back.

You need a new mechanic. A clogged cabin filter will decrease the output of air, but it won’t heat the air up.

If you really want to get to the bottom of this, you should take it to a mechanic who knows more about air conditioners.

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I agree, but I’m pretty sure he and I both charged it properly.I think he mentioned the cabin air filter was causing the vents to be different temperatures. He’s kind of hard to understand because he has a thick accent. At least I know it’s either an airflow or speed related issue now because it was ice cold on the interstate. Narrowing it down.