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Low Side Service Port different?

paradox on Tue May 25, 2010 5:08 PM User is offline

Year: 2003
Make: Pontiac
Model: Grand Am
Engine Size: 2.2
Refrigerant Type: R-134a
Country of Origin: Canada

I am trying to top up the R-134a in my daughter's 2003 Grand Am, however I cannot connect my quick connect to the low service port.
It is the 13mm quick disconnect port and while my connector will go on (it is the right 13mm ) it will not lock. The port on the line seems too high by about 1/8 inch, and my connector is not deep enough. It fits fine on my Buick Lucerne and Buick Lacross. Are the low side service ports different (higher) on the Pontiac Grand Am than on other American cars?

Thanks for your help.

Edited: Tue May 25, 2010 at 5:59 PM by paradox

Chick on Tue May 25, 2010 6:27 PM User is offlineView users profile

No, same size, but are you using a quality manifold set, or a recharge can?? if the recharge can, it might be good that it didn't hook up.. If using a manifold set, make sure the connector is open all the way, some you need to wiggle a bit and they will connect, and make sure it is the low side...

Email: Chick


Freedoms just another word for nothing left to lose

paradox on Tue May 25, 2010 6:55 PM User is offline

Thanks for the reply. No, my good quality manifold set has R12/22 fittings, and haven't used it in years, since I got old and can afford new cars. Although no professional by any stretch of the imagination, I pretty well much know what I am doing, and have used the cans before on the kids/friends cars and have no problems. (I know you professionals do not approve of the cans)
That said, the service port fitting on the Grand Am is a full 1/8 inch higher from the ball snap ring than the one on my Buick Lucerne, on which the can fitting, fits just fine. The Grand Am has factory AC.
Thanks for the assistance anyway.

GM Tech on Wed May 26, 2010 7:05 AM User is offline

I've never heard of this before...although that connector is NEVER used during factory assembly- (cap comes on the hose, and is never removed while car is being built)- It is possible that a bad port was built, and never caught- until now.....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

mk378 on Wed May 26, 2010 10:59 AM User is offline

Cans are OK as long as it's not "leak stop," "high mileage" etc -- just plan R134a. It's risky to try and "top up" anything without watching the high side pressure though.

You can buy adapters to use your old manifold set on R-134a cars. Like GM Tech said, sounds like a faulty port as it's not supposed to be different from other cars. A place with a charging machine could force a charge in through the high side like the factory does.

Edited: Wed May 26, 2010 at 11:01 AM by mk378

fizzeedisc on Wed July 10, 2013 4:17 PM User is offline

OK After reading and looking some said it was a green cap some said a blue cap some said it was up front some said it was on the fire wall.. so the answer is , Its a blue cap and you cannot see it it !! look directly in the BACK of engine in the center , look all the way down you will see 2 aluminum large line , reach your hand down and follow the line it will curve around a bit and you feel it!! but wont see it it .. just unscrew and plug the refill line .. Have an Awesome day ! 2003 Grand Am 6 cylinder!

Andre Cournoyer

fix_it on Wed July 10, 2013 10:31 PM User is offline

The green cap is for the evaporative emission system. It allows you to use nitrogen to pressurize the fuel system to check for vapor leaks. Has nothing to do with the AC.

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