my turbo went out so we replaced it along with the exhaust manifold, and thermostat housing. Its now overheating. We have bled the coolant system by filling the res, opening the bleed valve until its flowing, closing it and then idling at 2500 rpms with heater on full to bleed air. temp stays at just below half way like normal until I drive it and then the temp will peg all the way and the famous AC shut off due to overheat comes on. Help! what are we missing??