a/c question
 

hi guys, can someone please tell me how much r12 i need to put in my system? blazer 1990 5.7L..

Are you topping off or refilling a system from scratch ? If from scratch are you using small cans or a 30 lb bottle . Don't mean to be difficult would jsut help to have more info .

actually i figured out how much i need, but i got a different problem now.
i rebuilt almost my entire a/c system - new evaporator, new accumulator, new compressor, orifice tube etc.. i started fresh with 1.47kg of r12.
the actual cooling sucks so i came back to the shop only to find out that the high pressure is rising after a few minutes of work.
the man at the shop said the condenser (the only old part in the system) could be clogged or maybe it's too dirty to be able to clear the heat away.
he took a hose and splashed on the condenser and the pressure immediately dropped.
whenever is turn on the a/c i can hear noises from the steering pump and from the idler tensioner, the shop said that because the system now works on high pressures it applies extra tension on other components such as a faulty steering pump etc..
a new condenser will actually solve this problem?

before you go buying a condensor , check your belt tension, cause that could be causing your squeaking your hearing , also the fact that you say if you put water on it /it works better tells me that you are not getting rid of the heat , check your fan clutch (if you have one ) check to see if your condensor is plugged , is your fan shroud in tact ? is your condensor smashed over from washing it out , or debris?
or full of bugs ? this sounds like your problem to me !

actually i thought about it a few days ago and I've been meaning to ask about the fan clutch.
i noticed that when the a/c is on it doesn't appear that the fan is going faster.. i can see an electric plug coming out of the fan so it must have a clutch right? any tips for how to diagnose the fan clutch?

well if it has an electrical plug ,??? it could be an electric fan?? (didnt think they used them untill the next gen ?? could be aftermarket ?
if it is like it came from the factory , it will have an alluminum hub (viscous hub) in the middle of where the fan attaches to the waterpump. it takes a huge wrench to take it off ( normally left handed threads ) it is activated automaticly by temperature , the actual fan, the steel part, comes off the viscous hub (four small bolts) i have told several ways to check it , but unfortuneatly i have not had good luck with any of the methods ! if it is really loose and it doesnt take much force to turn it with the engine turned off ??? replace it ! if the engine has a electric fan , then you are getting into a whole other realm ! there are temperature switches and relays involved in this type of fan ! quite a bit harder to diagnose !!!