Remove Rad cap fill it to level-now start the car make it idle -look inside the radiator do you see the coolant squritlng around if so, pinch the upper hose for a few secs and let go do you see any increase of coolant flow if not review below. Also try bleeding it
Always bleed air from cooling system after replacing coolant. Set heater for maximum heat. Remove radiator cap. Loosen drain plug and remove drain bolt (if equipped) from engine block. Drain coolant reservoir. Fill coolant reservoir to MAX mark with 50/50 water-coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks.
Water pump -- Any wobble in the pump shaft or seepage would call for replacement. In some instances, a pump can cause an engine to overheat if the impeller vanes are badly eroded due to corrosion or if the impeller has come loose from the shaft. The wrong pump may also cause an engine to overheat. Some engines with serpentine drive belts require a special water pump that turns in the opposite direction of those used on the same engine with ordinary V-belts.
It does not happen very often, but sometimes the water pump impeller can loosen up on the pump shaft and not turn, although the water pump pulley appears to be turning normally. If the impeller does not spin, there will be little or no circulation of coolant through the engine. The only way to know if this is the problem is to remove the water pump and check the impeller to see that is is tight on the shaft. Also, some plastic impellers can become severely eroded over time. So can the water pump housing. The loss of blade area or an increase in clearance between the housing and impeller will reduce the flow of coolant and can lead to overheating.
Friday, November 16th, 2007 AT 8:38 PM