AC Problems

Tiny
OCTEXAS
  • MEMBER
  • 2006 CHEVROLET IMPALA
  • V6
  • AUTOMATIC
  • 160 MILES
We knew the ac did not work and tried adding Freon. We checked and it had was full. We then made sure the air compressor was running and it was. Is there anything else it could be? The heater works and when we change it to cool it just blows air. We are really frustrated at this point and hiring someone is not an option. Thanks in advance.
Sunday, July 5th, 2015 AT 4:36 PM

41 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
How much Freon did you add to the system? How long is the compressor staying engaged? Do you have gauges to check what the low and high side pressures are?
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Sunday, July 5th, 2015 AT 6:43 PM
Tiny
OCTEXAS
  • MEMBER
  • 3 POSTS
We actualy didnt have to add any it had 55 psi. We looked closer at the compressor and it actully isnt spinning. We should get a new compressor tomorrow. Thanks i'll reply how things go tomorrow.
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Sunday, July 5th, 2015 AT 7:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Before you do that, jump the low pressure switch to see if the compressor will engage. Also, check fuses and see if there is power to the clutch on the compressor and let me know what you find.
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Monday, July 6th, 2015 AT 8:30 PM
Tiny
MDSARRETT
  • MEMBER
  • 1 POST
If your compressor isnt spinning replace the compressor relay first Its a larger fuse under the hood in the fuse box
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Saturday, June 29th, 2019 AT 6:49 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Thanks, that's good advice.
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Saturday, June 29th, 2019 AT 9:31 PM
Tiny
IANMCDCA
  • MEMBER
  • 14 POSTS
  • 2006 CHEVROLET IMPALA
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 260,000 MILES
So I own several GM cars and vans that I run as taxis. I have been repairing them myself for eleven years. I have never come across this issue. This is a Canadian Impala with 48,5000 kilometers on it.

I have replaced the compressor twice (failed units) as well as the condenser and expansion valve. The system has been flushed. Orifice replaced. Still not cold inside and no sweating either on the lines or dripping from the car. Pressures on an eighty degree day are approximately 35-40 low and 150-180 high side at 1500 rpm. The blend door works: no hot air and lots of flow. I added approximately 1.2 oz of oil as that is what I lost in the replacement. Also added app. 1.6 lbs of aftermarket 134 equivalent The question: is it possible that a dirt filled evaporator would allow air flow but because the whole system to run warmer than it should? I am really stumped. Thanks in advance.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
The high side is not high enough it should be about 240 high side pressure. Here is a guide to help.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please run down this guide and report back.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
IANMCDCA
  • MEMBER
  • 14 POSTS
Thanks for the reply. New orifice screen already. And yes, I'll refill to that spec but it has not for the second season dripped from the EVAP case but the hole is not plugged. And never any condensation on the lines under hood. All my other vehicles sweat from those lines. When I flushed the system, everything flowed well and again, the gauges do not imply a blockage.
Thanks again !
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
If you grab the suction pipe where it comes our of the firewall, is it ice cold?

If you touch the liquid line after the condenser, what is the temperature? Is it ambient temp, warm to the touch or hot to the touch?

What happens to the pressures and temp if you bring the RPMs up to 3000?
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
IANMCDCA
  • MEMBER
  • 14 POSTS
So here is the scoop. I evacuated and refilled the system to correct weight. Ambient temperature is 85. At 1500 rpm, High side is 150-175. Low side is 32-38. At 3000 rpm, high side is 150-195. Low side 28-36. Suction at firewall is slightly cool. Liquid line is too hot to touch off the condenser.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
If your liquid line is too hot to touch, that indicates the condenser is not doing its job for one reason or another.
Try this. With the AC on high, get a garden hose and start spraying down the condenser and see if the suction pipe and the vent temperature get colder.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
IANMCDCA
  • MEMBER
  • 14 POSTS
I will try that. Fans come on but not high speed and they are not always running. On a day like today I think they should be.

Thanks for the quick reply! Just to be clear: the liquid line off the condenser is the smaller one correct?
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The pressures are not high enough to trigger high fan which is surprising. There could be a number of reasons for that. You could have a bypass type condenser that can be 75% plugged up and still not raise the pressures. You could also have a service port that is positioned on the far side of a blockage so it is unable to see the high pressure.

There is something else not right here.
You stated you replaced both the expansion valve and the orifice tube. That is impossible. The system cannot have both. All the information I see shows this as an expansion valve system so assuming that is true, if you also installed an orifice tube also, remove it right away.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
IANMCDCA
  • MEMBER
  • 14 POSTS
What GM calls an orifice on this car is just a screen. It is not the same as the older system.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
WILLYDUMAS
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 86,000 MILES
Mother in laws car dosen't blow heat while sitting idling. What do you think?
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
FACTORYJACK
  • MECHANIC
  • 4,159 POSTS
Check and make sure the coolant is not low. Often times at low engine speeds, the water pump cant deliver hot water continuously through the core if the level is low. Do you also hear sloshing noise when accelerating?
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The term "orifice" means small hole. You cannot have that before the expansion valve. They both do the same job.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
Definately a flow problem. Could mean a partially plugged heater core?
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check condenser for two things if there is a "bug screen " rip that off and throw it it cuts air supply down at least 15% then see if condenser is full of stuff. You might because of temperature put a fan in front of car and see if that changes things as well.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)
Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
According to 1 report any air in system causes this problem. Check to make sure radiator is full.
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Monday, August 26th, 2019 AT 11:24 AM (Merged)

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