Hello, I need to recharge the ac on my 99. I would like a little direction on this. I have not been successful finding anything through a search so any advice would be appreciated. Thank you.

 

If it needs a full recharge best to take it a shop with the proper equipment to pump it down and replace with the right amount. If you just need to add a little R134 you can probably do this yourself. Why does it need a recharge?

 

It is not blowing cold air this year. It is almost cold however not enough to keep up with the warmer days.

 

three ways to do this.
1. You can evacuate the system and weigh in the correct amount of refrigerant. This is the proper way to do it.

2. You can put gauges on the high and low side and put in refrigerant until your pressures are in range.

3. You can use a sight glass if one is installed in the system, and add refrigerant until all the bubbles are gone. Lack of bubbles means the evaporator is completely flooded. This is where you get the best cooling.

Since you are asking, I'm going to assume you are wanting to purchase refrigerant from the parts store, and add some. You most likely have a leak in the system, so this is just a temporary fix.
You will need a low side hose with a gauge on it, and a can or two of refrigerant. (134a)

attach the hose with gauge onto the can of 134a, and the other end of the hose to the low side connector. I believe it is next to the battery. Has a black cap on it. Much the same as a Schrader valve for your tires. The hose snaps on just like an air hose connector. You have air in the hose, and that air is going to get into your system, but there is a way to purge that air out. I won't cover that part as it is hard to explain.

Once the Freon is hooked up, and the valve is open, you can turn on the compressor and put the blower motor on high. The compressor will suck in the Freon from the can. The low side will be around 35 to 40psi. this is totally dependent on the outside temp though, so you need to use a conversion chart for 134a. I'm sure there are videos all over the place where you can see this done. I saw a commercial the other day on TV where they have a trigger you pull once the hose is clipped on.

Didn't see a gauge, so don't know how you keep from overcharging the system. Looks like a good way for someone who doesn't know better or have the proper tools.
Hope this helps.

Edit: Actually there is a fourth and very accurate way of charging an A/C. I didn't mention it, because it isn't used on automotive systems as widely as in residential split systems. It is called the superheat method. I was a certified A/C tech back in the mid 80's, and a lot has changed since then obviously. I hope I'm not misleading anyone as I am not familiar with a lot of the new ways of charging a system...

 

Searched worked for me...

http://forums.corvetteforum.com/c5-g...-ac-101-a.html

and if you need to change it ever..

http://forums.corvetteforum.com/c5-t...post1571637102

 

If it has lost charge then you have a leak. I'd recommend injecting dye into the system and charging it. Check for leaking dye after using the a/c awhile.

 

Please go over how you purge air from the charging hose? Hypothetically at least, the only way I can imagine achieving this is by opening the 134a flow slightly and vent to atmosphere as you are connecting the hose to the low pressure port

 

Thank you for the info!

 

That is how I do it, but I do it backwards. I connect the hose to the low side port, and loosen it at the other end. If the hose is one piece, then it gets complicated. You just have to do as you suggested.

 

I usually have to charge the wife's 99 A/C about every 18 months to 2 years. This last time I got it on the nose, it blows 40 degrees out of the drivers door when it is 90 degrees outside. The A/C has never worked this good since we have had the car, even after the dealer charged the system. Got to have set of gauges and use the graph in the service manual.

 

I can always count on the good people from the forum to help out. My ac is now cold enough to turn my wife's head lights on!

 

pics of said headlights.....