so i installed ac on my girlfriend's 99 civic si (condensor, lines, etc. etc.), got it vacuumed, checked for leaks, and charged and now as she accelerates into higher RPMs (stop and go traffic that is) the car will over heat. as far as i know all sensors and lines are connected and ac blows cold. what could cause this problem?

 

rad. fan working good?

 

was car overheated before install the ac?cause ac has nothing to do with car being overheated.is the water bump work?radiator fan?

 

um.....extra load on the engine

 

This is just a guess but if the radiator was already on the way out and you never noticed cause there was no condensor and now there is something sitting in front of it, it will overheat.

first couple of things to check is
grab both hoses and make sure they are both warm to make sure thermostat is opening, then try and find a way to take a temp at upper hose and lower hose it should drop at least 20 degrees then of course make sure the fan is coming on when it is supposed to. finally look in radiator after thermostat is open and check for flow to see if water pump is functioning. if you see any kind of debris what so ever in radiator you might as well get a new radiator and flush out the system.