Car's A/C not working

Tiny
NOAH956
  • MEMBER
  • 2007 CHEVROLET IMPALA
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 179,684 MILES
My cars A/C just stopped working all of a sudden. The car blows air but it's not cold. When I press the A/C button the light just flashes. I Checked the refrigerant level with a gauge and it said it was low. After doing a recharge the car blew cold air again but the next day it started blowing hot air. The refrigerant level now says it is low again.
Friday, September 27th, 2019 AT 2:57 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,788 POSTS
Welcome to 2CarPros.

There has to be a leak in the system at some point. Here is a link that explains how to find a leak in an AC system. Take a look through it and let me know if it helps.

https://www.2carpros.com/articles/air-conditioner-leak-detection

Take care,
Joe
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Friday, September 27th, 2019 AT 8:54 PM
Tiny
NOAH956
  • MEMBER
  • 24 POSTS
Don't really know much about car repair but while checking the AC hoses I did find a green substance near the o-rings. Is this where the leaks could be coming from? (Pictures attached)
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Sunday, September 29th, 2019 AT 4:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,788 POSTS
Welcome back:

Yes, that is most likely the cause.

Let me know if you need anything.

Joe
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Sunday, September 29th, 2019 AT 5:05 PM
Tiny
NOAH956
  • MEMBER
  • 24 POSTS
What are the parts called that need to be replaced? Just the AC hose assembly?
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Sunday, September 29th, 2019 AT 5:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,788 POSTS
Based on what I see in the pictures, the lines are going to what is called an expansion valve. In this case, there is a good chance the valve isn't the issue, but rather the o-rings that seal the system have failed.

I'm going to provide the directions for replacing the expansion valve. Once you get the system drained and remove the lines, inspect the o-rings first. They just may be bad. Also, once this is done, you really should have the system vacuumed down and then recharged. Also, when it is under a vacuum, if it maintains pressure, then you know the leak is fixed before you even put the Freon back in.

Here is a link explaining how that process is done:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

__________________________________

2007 Chevrolet Impala V6-3.5L
Thermal Expansion Valve Replacement
Vehicle Heating and Air Conditioning Expansion Valve Service and Repair Removal and Replacement Thermal Expansion Valve Replacement
THERMAL EXPANSION VALVE REPLACEMENT
Thermal Expansion Valve Replacement

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure

1. Recover the refrigerant from the A/C system. Refer to Refrigerant Recovery and Recharging.

pic 1

2. Remove the evaporator tube to thermal expansion valve (TXV) nut (1).
3. Disconnect the evaporator outlet and inlet tube from the TXV.
4. Remove and discard the sealing washers.

Important: Cap or tape the open evaporator inlet and outlet tubes immediately to prevent contamination of the refrigerant system.

5. Cap off the evaporator inlet and outlet tube.

pic 2

6. Remove the TXV to evaporator bolts.
7. Remove the TXV from the evaporator core.
8. Remove and discard the sealing washers.

Installation Procedure

1. Install the new sealing washers onto the evaporator core.

pic 3

2. Install the TXV to the evaporator core.

Notice: Refer to Fastener Notice.

3. Install the TXV to evaporator bolts.

Tighten the bolts to 7 N.m (62 lb in).

4. Remove the cap or tape from the evaporator inlet and outlet tubes.
5. Install the new sealing washers onto the evaporator inlet and outlet tubes.
6. Install the evaporator outlet and inlet tube to the TXV.

pic4

7. Install the evaporator tube nut (1).

Tighten the nut to 17 N.m (13 lb ft).

8. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging.
9. Leak test the fittings of the component using J 39400-A.

Let me know if this helps.

Take care,
Joe
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Sunday, September 29th, 2019 AT 8:17 PM

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