Charge port for A/C - System recharge?

TONY WALL

MEMBER
2006 CHEVROLET SILVERADO
6.6L
V8
4WD
AUTOMATIC
430,000 MILES

I am attempting to diagnose and repair and recharge my AC system on my Duramax Diesel 3500 pickup truck. I have attempted to hook up the manifold gauges to test the system but cannot find the high side port to connect the red line to. I did find a port directly behind the alternator, but it appears to be connected to the fuel system perhaps and not the AC system. I actually did connect the red line to it and pulled a vacuum, but noticed if I wiggled and pulled on the connection it would come off. Unlike the low side quick connect which remained firmly attached. I felt it should fit better especially since it is under a great deal more pressure. This caused me to question whether it was indeed the high side port? It did have a shrader valve stem in it and was very close if not the exact size of the red quick connector on the gauge set. Can you verify if this is the high side port and if not, where is it or how do I connect the manifold gauge set without such a port? I am new to this, but have spent hours trying to find an answer. Any help you can give me will be greatly appreciated.
Thanks,
Tony

8 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,895 POSTS

Hello,

There is only one high side service port which will be on the hose going out of the compressor and onto the condenser or after the condenser to the evaporator. this video will help you find it.

https://youtu.be/ON2dYcmXIAw

Here are a couple of guides that should be able to help you.

Here are videos and guides to show you how to recharge your air condition system and find the charge port.

https://youtu.be/uZrQCGwXfek

and

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

and

https://youtu.be/ON2dYcmXIAw

and

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

and

https://www.2carpros.com/articles/how-a-car-air-conditioner-works

Let us know what happens and please upload pictures or videos of the problem.

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Monday, May 29th, 2017 AT 2:13 PM

CW4RKELLEY

MEMBER
1 POST
2005 CHEVROLET SILVERADO

What is the correct Freon amount for a AC recharge 2500HD truck with a 6.6TD, front air only?

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Friday, April 30th, 2021 AT 3:36 PM (Merged)

MERLIN2021

MECHANIC
17,250 POSTS

1.60 lbs R134a 0.7 KG. Here is a guide to help you recharge the system.

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

Please let us know if you need anything else to get the problem fixed. Cheers

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Friday, April 30th, 2021 AT 3:36 PM (Merged)

LEXYANDARIANA

MEMBER
1 POST
2003 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
65,000 MILES

My AC seems to be working okay. I get it to about 42-44 degrees on setting 2, when I turn it up to setting 5 it seems to lose is coolness. I have been using a candy thermometer to test it and it just does not seem to get cold enough. My wife's Grand Caravan get to about 36 degrees. It takes my truck a good amount of time to reach 42 to 45 degrees. How cold should it get and how do I locate the low pressure side so I can recharge it if needed? What else could cause it not to get colder?

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Friday, April 30th, 2021 AT 3:36 PM (Merged)

KEN L

MASTER CERTIFIED MECHANIC
42,895 POSTS

Hi,

It sounds like the system is a little low on Freon. Here is a diagram on where the low side port is which is on the side of the accumulator, and here is a guides that will help you charge the system correctly: