Re: Air conditioner charging question?

Well, first of all i don't trust the gauges on the cans. If you don't own a good set of high/low side gauges, invest in a temperature gauge, which you would place in the middle vent inside the cab. That gauge should read between 30 to 45 degrees.

Your low side should read between 40 to 50 on the low side. When charging on the low side it should be put in as gas ( the can right side up and not upside down) If charging from the high side (with correct gauges only) it will be put in as a liquid. If your not familiar or comfortable with A/C stick with the low side charging. :)

---------------------- How do you charge through the high side with just gauges? I'm suprized you still have all your fingers. ;)

It is normal for the compressor to cycle even when the heater is on. This keeps everything in the system moving, rather than just sitting in the system.

Thanks Scott.

It does not cycle and is nice and cold. Since I am the second owner of this truck I don't always know what is "normal". I am pleased that one can of freon (with oil & sealer) seems to have fixed it even better than my expectations. The part that is confusing is that the cheapy gage that came with the kit only seemed to indicate a rise in low side pressure of one pound. Although I did read somewhere that 25 lb.s up to about fifty is OK as long as it is blowing code air. Perhaps 25 lbs. is normal for this system. I was hoping someone in this group would be able to say definitively what the pressure should read for my truck. Also, as someone else has suggested in this thread, I probably should have spent the money for a proper set of gages.

For now I will live with it as long as it continues to cool well.

Thanks to everyone for your input.

Paul

----------------------------- ya, there is nothing wrong with 25lbs.if it is cooling well and not cycling alot. The low side will change with the outside air temp(lower/lower higher/higher) and it sounds like the gauge isnt working right anyway since it shows the same after the 12 oz addition. But it doesnt matter anyway because if it cools good-no promblem. I always smile and shake my head when I hear the ads for A/C check for 49.95. I'm sure it makes people worry about their A/C even when it is working great. Its kinda like, here's 50 bucks to tell me my cold A/C is OK, or if it isnt working take my $50 to tell me why and what parts I need. I guess thats one way to get around free estimates....Then theres the trick of checking your A/C by pulling YOUR freon out and then pumping it back in and charging you $10 a pound for your own freon. And of course add $50 labor to do it. (I guess you could say you are paying to filter it) LOL

A few questions...if he only added 14oz of freon to the system and the system was already at 24lbs, wouldn't 25lbs be correct? After all 16oz makes a lbs. Or is it somehow different when working with a/c systems and freon???

Next question, my girlfriend has a 92 Chevy long bed truck with a 350. It has been retrofitted to R134a, it seems to squeel a bit when she is idling for long periods on really hot (100*) days. I added a bit of freon to the system, which seemed to help for a bit and then we also replaced the belt, which also helped out. It is not nearly as bad as it was, but it still will squeel on occassion. I don't have a guage, but suppose I could try to get ahold of one, I just hate to spend $$ on something I probably won't use but maybe every few years. I guess part of my question is this....her system does seem to be cycling on and off a lot, after reading this, I am guessing she may be fairly low on freon. If I take a reading at the vent and it's above 45* should I add some more freon?? Also, is the low side the larger or smaller fitting on a R134a system? I just don't mess with these enough to remember.

Thanks

You really need gauges to properly diagnos. Sounds like the belt is squeeling or is it the pulley bearing? Maybe it is something else making the noise? There are other problems that can cause it to cycle too much. With out gauges you cant tell for sure. The large hose is the low side. you can try adding freon to see if it cools better and cycles less. Just wear eye protection. If there is a problem like the exansion tube partialy plugged it will make it cycle and the high side will sky rocket risking blowing a hose or at least blowing the pop-off (if it has one) if you overcharge it. It is also important to keep the condensor and radiator clean. If there is dirt and bugs ect. it will not cool as well. (this will not cause the cycling) usually some of the crap gets stuck between the radiator and condensor so you cant see/clean it without removing the top of the shroud to get at it with a garden hose.

Thanks, I'll look into these items!!

actually, no. the system would be at 24 PSI, not 24 pounds of refrigerant. auto AC systems have around 2 lbs of refrigerant. 14 oz of freon should

*significantly* affect the pressure of such a small capacity system.

is your belt system in good order? the early years of the 88-98 gen were notoriously noisy when the AC is going. my 88 K2500 groaned like crazy when the AC worked in it, my brother's '93 c1500 has a completely different belt setup and makes no extra noise when the AC is going.

you also might want to try giving the belt a shot of belt dressing.

I don't have a guage, but suppose I could try to get

I *think* AutoZone has refrigerant gauges as part of their free loaner tool program, try there or a similar DIY focused auto parts store.

I guess part of my question is this....her system

45's actually not all that bad for a converted system. my wife's Isuzu Rodeo's vent temp is 46F and it cools us just fine.

Also, is the low side the larger

can't tell you off hand, but it should be the one on the larger tube.

HTH, Bret

I can see that if it's at 24 psi, it should be affected more. That makes sense. I guess he must have typed that incorrectly and confused me. I guess 25 cans of refrigerant would be outrageous. I also think 2lbs sounds like a low number, I thought my Honda took 3-4 cans, but it's been a while and I forget these things. I find out when I do it and then forget, as I only tend to mess with this stuff once every 3-4 years if I'm lucky.

On her truck the belt is brand new. The idler pully might be wearing out and causing some of the problem, haven't had a chance to diagnose that, but a friend thought it looked a bit worn. Her truck in a 92, and I have a 92 'burb, same engine, and my AC is very quiet, and it also has been retrofitted, so I am guessing it's something else. As for putting belt dressing on, I never seem to have luck with that stuff. It's sometimes handy to find out if it is the belt or something else, but it never cures a squeeky belt for me.

Thanks for the input...I think I will take the temp of my system and then compare to hers. The only difference is that I have rear ac in my 'burb, where her truck obviously doesn't...

refrigerant.