I'm new to working on cars, and I've done some smaller things like changing oil, but this was my first time charging the AC. I knew for a long time that it was low, but was quoted over $100 to charge it, so I decided to do it myself.


I have a Honda Accord SE '97 and I followed exactly what it said on the can, and what I could find online, I let the car run on MAX AC for around 3-4 minutes, and then started to charge it, after hooking it up to the LOW pressure line, shaking the can every 3-4 seconds, and turning the cap so it charged evenly. But after around 7 minutes or so of charging, I was around maybe 17-18psi, and the psi suddenly jumped up to over 65, probably around 70 when I disconnected it and pretty much ran from the car.

I let the car run for a few minutes while sitting inside with the AC still on high, and hooked the pressure gauge back up, and after a few moments it read at 25 psi, and didn't move. I unhooked the gauge and the freon can and have had the car idling for about 17 minutes now, and I'll check the PSI again, but I also have another problem that I saw on here, I've noticed the the AC is cycling probably every three to four minutes, turning on and then back off, and then back on again.
I've also noticed that when the AC is off, it has this drivers side grinding noise almost, but it's more like a whirring then a grinding. I'm really worried that I overcharged the AC, and I don't quite have the money at the moment to visit a dealer and get a full decharge, vacuum, and recharge, so any advice about what to do would really be helpful.

-D

 

Without the high and low side readings it is kind of hard to know. Also knowing the temp at the vents and outside would help. Depending the the pressure readings, outside temp, temp at the vents...all guesses from here. The compres going thru cycles could be normal, again with temp and pres readings?? Was the noise there before the charge, strange it is there when the compres/ac is off. Shouldn't be any "stress" on the compressor when the clutch is not engaged.

I know there isn't an answer to you question in the above. Instead of the dealer, is there not a local shop or ac specialist that will do a "free" or low cost inspection?

Last, where are you located. Most of of us in NA are more worried about heat in the car than ac right now.....

 

Sorry about a late reply, but I'm in Cali right now, and the outside temp when I was charging it was probably around 65-70*F. As for the vent temp, I can try to find a way to check it, but I'm not sure if I'll be able to. I was watching the compressor and radiator fans when the noise started and stopped, and it seems that when the fans are off, the noise stops as well, but it's as soon as they're disengaged, and it returns as soon as they are reengaged, no matter the speed of the fans.

Also the volume of the noise increases with the range of the RPM's of the engine, regardless of how high the vent speed is, if it's on the lowest or highest setting it's the same.

I rechecked the pressure of the low line before I shut down the car, and when the AC is on, it stays at a steady 25psi, and when it shuts down, it goes up to just above 55psi, and it's steady at both times for more then 30 seconds.

As well, it's also been really rainy here for the past four days or so, I don't know if this would effect anything as well.

 

this psi reading will not tell you if your charged this tells you when your psi on the low side gets to that cut off pressure its working right. but if your low side is achieving these psi's one after another,

Example turn the car on, turn the max a/c on, turn recirculation on and close your windows. let run for 5-10 min.

Now hook up that pressure gauge I'm assuming is on a 1lb can of r-134a and watch the pressure

If your pressure cut off is 55.

When the compressor kicks on you will see it climb to 55 and then the low pressure switch will kick the compressor off. then a little slower than it climbed to 55 it will drop to around 24.

the colder the in car temp the slower the low side pressure readings will rise and drop because the evaporator isn't absorbing much heat therefore the pressures stay cold/low. hints good a/c.

but if you are hooked up and see the pressures rise like that, and the compressor is kicking on and off about 3-5 times a min, and the temp coming out of your CENTER ducts is around 35-45 i would say your pretty good.

the squealing noise if its coming from the compressor i would say your clutch air gap on the compressor is out of adjustment.

Good Luck,
NWOrphan

 

it cut the first half of my message away for some reason. but 25 psi is a very normal number when the compessor is off. but as long as you have good low side pressures, compressor doing it 3-5 time a min thing and you have 35-45 temp coming out the duct your good.
at 75degrees and not 90% humidity your compressor should only kick about 2-4 times a min also depending on in car temp