refrigerant capacity

I have the same Truck, it holds 3 lb 7 Oz.

 

Fan should come on, compressor shut off, till pressure drops. I think you put too much oil in it. May not matter. May cause compressor to run hot. Separate issue. Sounds like the high pressure side of the high pressure/fan switch is bad.

 

I typically add 3 Oz of oil, if I think the system is low. Usually some oil stays in compressor, and condenser.

 

Pull the cover off a/c heater box and ck for the temp probe that Should be stuck in a/c evop. and not have any breaks in it, thats what makes the a/c comp. turn off before it freezze. up.

 

Checked up on oil. 1.5 Oz per lb. max 2.0 Oz. Per lb. So 55 Oz. 134a, 6 Oz. Oil, or 5.15 Oz -6.875 Oz. Max

 

Good info, I always thought it turned compressor on. Makes sense though, good to know.

 

I’ve read before that too much oil displaces refrigerant, and not only affects cooling, but makes compressor run hot, shortening life. Sandens suggests it’s better to have too little, than too much. That was a surprise, as I used to add a little extra, thinking it was good for the compressor bearing. Had no idea, compressor relies on refrigerant itself for cooling.

 

Another thing to check, if you already haven’t, is obstruction in condenser fins, more likely radiator fins. May need to clean radiator, and maybe condenser fins to improve air flow. Usually the front of the radiator, behind condenser will be blocked with dirt, need to remove condenser, leaving lines hooked up, and spray it out good with water and air