Using A/C gauge manifold for adding freon
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
Using A/C gauge manifold for adding freon
What is the best procedure for purging air out of all the hoses before adding freon?
I know I can purge the line from the freon can by loosening the hose at the manifold and using can pressure, but do I also need to bleed the air out of the high and low side hoses?
Is it necessary to worry about the high side hose since flow "should" just be toward the manifold? (I assume the high side valve is closed during charging, and only opened to check the pressure?)
I know I can purge the line from the freon can by loosening the hose at the manifold and using can pressure, but do I also need to bleed the air out of the high and low side hoses?
Is it necessary to worry about the high side hose since flow "should" just be toward the manifold? (I assume the high side valve is closed during charging, and only opened to check the pressure?)
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
I was mainly trying to find out if there is a way using a manifold to add a small amount of freon from a can without evacuating the whole system... Looks like the people that charge a small amount with just a low side hose and gauge must be introducing some air everytime they add freon...
Short of pulling all the freon out, the only way to purge the hoses may be to use the freon pressure to push the air out of the hoses.
Short of pulling all the freon out, the only way to purge the hoses may be to use the freon pressure to push the air out of the hoses.
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
I would still ask though...has the system been open to the outside or has it just leaked a little freon out. I have an SUV that has a very slight leak at the case halves of the compressor. It needs, and I add, about one can of freon every other year. An inexpensive gauge can do this easily, but it couldn't if the system had actually ever been opened to the atmosphere. On a 15 year old SUV, I'm not going to do a new compressor when a $5 can of freon is all it needs every 24 months.
Racer
Joined: Dec 2010
Posts: 418
Likes: 0
From: South Central Kansas
Just let a little refrigerant out of the hose and the air will be gone. The only proper way to charge an a/c system is to pull a vacuum on it and put in a measured amount of refrigerant and oil.
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
Yes, if you are just topping off the system you can charge it through the low side hose. Try one can at a time, probably just half, until you have approx. 35lbs on the low side and 150 on the high side.
And yes, pop the can with the can tap and with both valves closed at the manifold, open the center hose and allow a little Freon to escape to purge the air.
There's really no 'home' remedy to purge air from the hoses leading to the vehicle.
And yes, pop the can with the can tap and with both valves closed at the manifold, open the center hose and allow a little Freon to escape to purge the air.
There's really no 'home' remedy to purge air from the hoses leading to the vehicle.
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
I would still ask though...has the system been open to the outside or has it just leaked a little freon out. I have an SUV that has a very slight leak at the case halves of the compressor. It needs, and I add, about one can of freon every other year. An inexpensive gauge can do this easily, but it couldn't if the system had actually ever been opened to the atmosphere. On a 15 year old SUV, I'm not going to do a new compressor when a $5 can of freon is all it needs every 24 months.
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Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
Then you can absolutely do it. Go to Walmart or an auto parts store and buy the can of R134a and get the one that comes with the gauge and a short hose. Follow the instructions on the package. You can use the hose with the gauge to check the pressure of the system before puncturing the can...you may not need any freon. The kit is $15 or so...no big deal. The instructions are very clear. Remember that unlike the standard line on the Corvette forum, more is not necessarily better...don't put in more than the instructions say. There was a recall on C6s a few years ago where they were overfilled with freon at the factory and it degraded the performance of the system considerably.