A few months ago my AC didn't seem to be blowing as cold, so I threw some more R-134a in there. It got cool enough, but not exactly "cold." Within a few weeks, it was warm again. Another recharge did the trick, but this time it only lasted for about a week. The pressure hasn't dropped, so I don't think there's a leak, but the air isn't cold anymore.

Someone mentioned something about evacuating the system when I recharge, but I don't know anything about this. Anyone want to shed some light on this? Can I do it myself?

 

You shouldn't need to "evacuate" or pull a vacuum on the system unless it's been open to the atmosphere. Sounds like a leak though - I'd try recharging it again with referigerant that has dye in it.

 

Evacuation can only be done by a several thousand dollar machine (not something the novice is going to have). I would say you are in need of professional service, anyway, so a trip to a trustworthy a/c shop may be in your future.

 

Yeah, the point of doing this is to get any "gunk" that may be in your system out. You evacuate all of the refrigerant and oil, then you pull a 30 minute vacuum on the system to get all the air and stuff out. You don't want ANY atmosphere air in the system because it contains water in the air and will inhibit cooling ability.

What are the pressure readings on the high side and the low side?

One thing you may want to replace is the orifice tube. It is basically the piece that separates the high side from the low side. It's like a $2 part. If it gets gunked up it will not allow enough refrigerant to flow and can hurt AC performance.

Get it done professionally and get dye added to the system so if there is a leak, you'll know it

 

Actually we don't have an orifice tube. We have an expansion valve, and it's $45.

 

cheapest one I have seen was $1200, and that was evac/recovery only

 

Yeah, good luck in finding an orifice tube.

 

At the shop I work at we charge $59.95 for AC service which includes evacuation, 30 min vacuum, leak test, and the cost for R134a is extra. It's so easy all you do is set the machine up and walk away and do another job, it's a real money maker.

 

Doh... I had a feeling that was wrong... lol. I just replaced the orifice tube in my 86 ranger. It had about 1/8" of mud CAKED all over it

lt1997: Yeah I love doing AC work at my dealership.