89 4.3 A/C Question

My A/C is out. No cold air. Figure I've got to recharge it, but how do I know if it's been converted to R134 from R12? Or what else can I use?
I've had the truck for two years and haven't had to deal with it.

If it's been converted it should have a sticker stating that, however it may have fallen off.

R-134 uses a small valve, so if yours has been retrofitted it'll have a screw on adaptor.

There are alternatives to R134 if it isn't converted. You can get R12B put in without converting anything. You might have to shop around for someone that will actually do it since they all want the money for an expensive conversion.

Also HotShot will go right in. Get the system checked for leaks first.

r-134 uses a quick connect style adapter whereas r-12 uses a screw on.

My A/C is out. No cold air. Figure I've got to recharge it, but how do I know if it's been converted to R134 from R12? Or what else can I use?
I've had the truck for two years and haven't had to deal with it.

A freon edifier is the only way for sure you can tell what freon is in it.
Some have blend or blends with a propane mixer.
89 had R-12 from factory but a lot was converted to R-134 and some just drop in blends.
If propery converted it will have a sticker on it and the high and low fitting changed to R-134 snap on fittings
But First things first.
Make sure it needs freon before adding.
Do not get or use one of them wal mart recharge death kits.
Or use a blend freon with a butane mixer.
Here is what you need to be safe and and do a proper check it on it.
http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=66773
With compresser running check low and high side pressure at idel and at 2000 RPM and post back low and high side pressure readings.
MT

Ok thanks everyone. I'll check it out this weekend.