So my A/C has been acting up a bit.
Early last spring I noticed the compressor cycling on and off rapidly.
Took it to the garage as I have very little knowledge about A/C workings.
He replaced both "hoses" as they were leaking at the connections and he recharged the system. All was fine until late July when I noticed on a long trip that the volume of air coming from the vents would decrease after about an hour or two of driving. Around town on short trips it was fine.
Been driving an awful lot over the past couple of weeks and on a 500 mile round-trip this past weekend, the air just went warm. No cold at all, but also no decrease in volume of air coming from the vents (someone in the A/C forum suggested that I may be running low on refrigerant causing the evaporator to frost over??? causing the decrease in airflow)
So, I figure I can at least put some more refrigerant in it until I get a chance to get it looked at to find out where it is leaking and what needs to be done.
When I researched the recharging process online, all sites made a very specific point that the system should not be overcharged (low side pressure <= 45 psi)
When I hooked the kit up to the low side of the loop, the gauge read 45 psi, so I didn't put any refrigerant in.

So, if any of you folks know anything about A/C that you can share, I sure would appreciate it. I am going to post this in the A/C forum as well to see what folks that visit that forum have to say, but I know most of you by reputation and am anxious to hear your words of wisdom on the matter.

 

Grap the hi-lo pressure switch on top of the compressor and pull it towards the engine. Sometimes this plug in is loose causing the compressor clutch to kick out. See if this will keep the compressor engaged. If it does, zip tie it over, worked for me. Cleaning the plug also helps.

 

Thanks. I did try pulling it lightly in different directions with the engine running to see if it made a difference. Doing so didn't do anything noticeable.
I have a trip coming up on Saturday and really am just wondering if it is going to hurt anything to try to put some more refrigerant in.
I guess the real question is this: If there is 45 lbs of pressure in the low side of the loop, does that mean there is adequate refrigerant for the system to work and that the fact that it is not working is due to some other factor?

 

on long trips in high humidity the evaporator will ice over, even more so if not running on max ac. a simple solution is to run on max ac and than when it starts icing over (warmer air from vents) switch to vent setting for about 2 minutes and than back to max ac.

 

i just had my compressor replace in june at first it wouldn't take i found it was a in line filter called an orfis tube. from what i could see it was trapping dirt from the old system i would also check that may want to replace the o rings

 

If you have 45 on the low side then you don't have to worry about the evap icing up. If it does then you have a lot of air in your system. maybe down around 20-25 with a clean charge but the clutch should kick out at that pressure. What is your high side reading? that is really important to know so I can tell if things are working right.

I'm assuming your clutch was engaged when you got that pressure. If not then it doesn't mean a thing. Your clutch should have kicked on at that pressure if it was working right though.
Also 45 is getting a bit high. I like them around 40 or just a bit lower. 30-35 at WOT.

ANY TIME you replace a compressor the orifice tube should be replaced. Also the dryer. If a shop doesn't do this they should be finding themselves in court real fast. I'd get my money back . They obviously aren't licenced and don't know squat about air conditioning.

Also if you got one of those cheap charging kits without a high side gauge then take it back. You have to see the high side when you are charging. if it's over 400 then you got problems. over 450 and you have major problems. It should be 300-350. I think 475 is where the relief valve will blow on it. Most trucks will get really close to that sitting in traffic on a hot day after some knuclehead has recharged them. I've seen it a lot around here a pop and a huge cloude of white coming out from under someones hood. I just laugh at them.

 

Thanks-
It is going back to the shop that originally replaced the lines on Monday.
I was really just wondering if there was anything I could do in the meantime as I have a 300 mile round trip on Saturday and I really hate driving on the highway with my windows down.
I have been using this shop for 25 years. They have always treated me right. If this is a result of something they forgot to do, like replace the orifice, they'll make make it right.
Thanks for your advice!

 

I know it's generally frowned on to use Voodoo to revive dead threads, but I just wanted to throw OldBird some reps. It really illustrates the effectiveness of this forum. The backstory is my a/c crapped out and I was sweating getting it looked at so close to the end of our hot season. Searched the forum, and found this thread, wiggled my wire (hee hee, that's dirty) and clutch kicked back on.

 

Not so lucky for me. Compressor was shot. Installed a new one and all is well.

 

Glad to help Mr. Nasty and thanks for the rep. I personally don't see anything wrong with bringing a thread back from the dead. Stay Cool