A/C question...

[QD]

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.

 

[5literbeater]

It sounds like you have a leak somewhere. Im a refrigeration tech. Try adding a LITTLE bit of dye. You don't need to add a lot. Then, using a black light, check for leaks. Check the condensor, evaporator, all connections, etc. If that doesn't work, pressure test with nitrogen. Go to about 150psi. Once the leak is found, repair it then you MUST use a vacuum pump to remove all non condensables from the system. Then use a scale to weight the refrigerant that you are putting in. There should be a sticker on the core support that tells you how much refrigerant to add. It's a bit more work but simply adding refrigerant won't fix your problem. It left the system some how and now you have got to figure out where its leaking. Good luck!

 

[Pengy]

Sounds like a dirty orfice tube to me... exact same symptoms I had, but you would need high and low pressure side readings to find out exactly what the problem is.

But it could also be a vaccuum line somewhere messing with the hvac controls and turning on the heater instead of the AC.