First the low side port should be identified, connecting w/ a set of guages- apply at least 28" of vacuum for ten minutes. If the reading on your guages (vacuum) moves (loses) vacuum in 15 minutes don't charge the system- you have a leak. If the vacuum guage doesn't move (leak) then charge with the proper amount of refrigerant gas.
== == Was built with r12, can be converted to r134a.
Check charge. (R12)
Should be 2 ports on your ac lines somewhere. they work like tire valves. You just plug in a can of r12.
You buy r12 at auto parts store then plug the can into a valve on your ac line. instructions will be on can.
Not the high side.
Would have been built for R12, can be converted to R134a.
I believe it is around 3 1/2#.
easily. Buy a converter from local parts store for r12 to r134 system should cost 6-10 dollars. Screw converter onto AC fittings and charge as a normal system Freon is about the same cost.
The 1990 Ford F-350 requires 52 ounces of R12 refrigerant. This is applicable to all engine sizes of this model.
The cost to charge an air conditioner in a Chevy Silverado 2005 truck, will depend on if it has a R-12 or a R-134a system. The truck should be taken to a mechanic who can charge the AC and who can also given an estimate of the cost.
R12
R12-if it has ac of course.