I've got an '88 F250 7.3L. When I bought this truck 3 years ago the air conditioning was not working. It wasn't a big deal at the time but now I would like to get it fixed. Since it has never worked I don't know where to begin. Trying to avoid having to replace all the parts one by one to fix it. Is there anything I can do to isolate where the problem is?

 

Check the system pressure buy just poking the shrader valve on the line that comes off of the evaperator there may not be any in there if so it "should" be reclaimed. Then open the line on the right side of the condenser that sits in front of the radiator and pull out that little prastic screen and clean it put it back together but you will need a new o ring they are of a special material and green in color. If you dont have any luck finding a replacement pm me and a can mail you one out of my stash. If the pressure in the system falls down the compressor will not engage the pressure switch is on the right side of the engine by on the receiver/dryer, make sure that is hooked up and make sure when you turn the air on you have power going to it. next make sure the compressor is hooked up and the clutch (face of the pulley) turns free. I would run a jumper wire to the clutch and make sure it engages. I'm assuming its still r12, and r12 is hard to get and you need a license to buy it. The easiest would be to convert to 134a. So get a set of quick connects for it they just screw on the r12 fittings most of the time they come in a retrofit kit. Me personally just buy a full system charge worth the esther oil and the rest just plain 134a. I have a small system evacuator that runs off my air compressor. This sucks all the oil and moisture out of the lines it pulls -29hg i run it through my gauge manifold for about a half hour to 45min then shut the valves off to hold the vaccum on the system overnight, if it holds overnight its usually good enough to charge. If it sounds like you want to tackle this i can give you instructions on chargeing the system.

 

with the engine off, make sure you can spin the compresor. The ft part of the ac clutch should spin. if it does, unhook the switch on the reciever/dryer and jump the terminals. with the ac turned on and engine running the clutch should engage. If it does you have a low charge and recharging should make it work until the freon leaks out again.

 

But remember if you don't see a retrofit tag or quick connects its probably r12 and you have to have it charged with r12

 

also hot shot you can use instead of r-12 it is not a drop in freon evac the sytem and refill with hot shot you need a linsce to buy it and it is only sold in 30 pound jugs... if it was me doing it i would change all the o-rings reciver, orfice tube and compressor oil and recharge it that is what i did as i have a linense to buy the freon the head pressure with hot shot is similar to r-12 and that is what the compressor and codenser likes...

 

Just out of curiosity what is that hot shot? Its not one of those r12 subsitutes made out of butane is it?

 

R-414b (hot shot) Used in air-conditioning and refrigeration systems—anywhere you used to use R- 12. blend contains 50% R-22, 39% HCFC-124, 9.5% HCFC-142b and 1.5% isobutane (R-600a). it is sold at RSD which is my local A/C supply house in Las Vegas, Nevada over there it sells for $100 for a 30 LB Jug . on my truck i usally carry R-22, Hotshot and R134

 

What kind of evap pressure do you run with the hot shot?