A/C help...

[quickdodge®]

Took possession, yesterday of a 1997 B2300. The A/C wasn't working when I picked it up. I had one of those rechargers that I had bought but never used a few months ago. I set the dial and turned the truck on and the gauge was just moving back and forth with a clicking noise every few seconds on the truck. I pulled the trigger to start adding refrigerant and after a few minutes of recharging, the clicking stopped and the gauge started actually registering. I'm guessing it was completely out of freon. So I kept charging and checking until I finally ran out. The gauge was at around 40psi. Instructions said it needed to be between 55-50, I believe. I got in the truck and it was then blowing ice cold.

AWESOME!!!

I got in it this morning to take it to get it washed and when I would drive, it would get to where it wasn't blowing out at all and then it would push hot air out. When I would slow down, it would start back up again with cold air. It's just back and forth.

Any ideas or advice? Thanks, in advance. Later, QD.

[green91]

I know you've already tried a self-recharge kit, but it would be worth your time to have someone with an actual AC evacuation & recharge machine pull the system down for you and charge it. Theres a couple reasons i say this:

1) When they evacuate the machine it measures the amount of refrigerant thats actually in the system to give u an idea if there was a leak, also if it had an overcharge condition.
2) when the system is evacuated, it also pulls out any moisture (hopefully none) in the lines that the desicant hadn't already absorbed (moisture can freeze up the expansion valve or other orifices)
3) The ONLY way to properly recharge a r134a is using a machine and it enters an exact amount of refrigerant in ounces. There's a label under the hood that indicates the system's volume.
4) At the time of recharge they also enter a combination dye/lube. The dye allows leaks to be found with a special light/glasses so the repair is easier. The dye/lube ALSO lubricates the compressor & expansion valve, making everything work more smoothly and quietly.
5) The a/c machine also has a gauge set so they should be able to watch the line pressures high/low sides and give you an idea if everything is working OK.

I know a lot of people moan about spending $70ish on a recharge through a shop but i think its one of the times its money well spent.

[quickdodge®]

I know a lot of people moan about spending $70ish on a recharge through a shop but i think its one of the times its money well spent.

That's all it costs? I'm all about it, dude. Thanks for the advice. And the rest of the post, lolol. Duly noted. I know nothing about this and wanted to try the cheap way out. It works enough, right now, to get me by until I get it to the shop. Thanks, again. Later, QD.

[green91]

Yeah, the dealer i worked at was around $70-80 IIRC. Obviously call around and ask but the best price.

[.:Stirfry:.]

you have a leak some where. when your driving down the road the low side pressure drops as the wind cools down the condenser, also the higher rpms the faster the compressor is going so less pressure thru the lines. then as you slow down the pressure starts to rise again then hits thats point where it turns on the compressor, boom cold air. (of course with the compressor engaged) but on the gauge on the low side its supposed to be around 35-40 with the size truck you have and high side around 150-250psi on a good charging system. but yea take it to a shop and they'll look it over