A/C intermittently blowing hot air?

JESS2968

MEMBER
2005 CHEVROLET TAHOE
5.3L
V8
4WD
AUTOMATIC
130,000 MILES

My A/C intermittently blowing warm air and would blow cold again if I shut it off for a couple of minutes it would work again. So, I started out by changing the A/C compressor, dryer, rear expansion valve, front orifice tube, both the high- and low-pressure switches and the main control unit in the dash. Now it still intermittently blows warm air for about 30 seconds.

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,607 POSTS

When you did the compressor did you add compressor oil? The reason I ask is because if you added oil the system could be overfilled with oil. Did the compressor come with oil prefilled? Next, when warmed up what are the high and low side pressures? This video can help us see what's going on:

https://youtu.be/4EqdrBVb0sY

These guides can help as well:

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

and

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

When the system is blowing warm is the compressor clutch engaged? Let us know what happens and please upload pictures or videos of the problem.

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Thursday, July 21st, 2022 AT 9:56 AM

JESS2968

MEMBER
13 POSTS

Hello, I did not add any oil to the system, yes, the new compressor did come with oil, but I removed it. I then took it to a shop to have it recharged and they put in 3 pounds of refrigerant in the system.

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Thursday, July 21st, 2022 AT 10:43 AM

KEN L

MASTER CERTIFIED MECHANIC
47,607 POSTS

When the system is blowing warm is the compressor clutch engaged?

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Friday, July 22nd, 2022 AT 2:05 PM

JESS2968

MEMBER
13 POSTS

I have tried to do that, but by the time I pullover and pop the hood it's blowing cold again. It does not do it just sitting idling. I looked up how much Freon should be in the system and it states 2.7 pounds not 3 pounds.

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Friday, July 22nd, 2022 AT 2:40 PM

KEN L

MASTER CERTIFIED MECHANIC
47,607 POSTS

Yep, too much can cause the high-pressure sensor to shut the system off. The high side reading should be no more than 260 PSI hot.

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

and

https://youtu.be/4EqdrBVb0sY

Please run down these guides and report back.