2000 Ford Taurus

Engine Cooling problem
2000 Ford Taurus 6 cyl Front Wheel Drive Automatic 86,000 miles

My 2000 Taurus needs a coolant flush (rusty film in system) but I need to know if there may be another issue as coolant purges out the cap of the reservoir after the car has been running at temperature for a while. Eventually, it purges enough to cause overheating and more purging. The reservoir is an aftermarket unit with vented cap. Electric fans are functioning but not sure if they are switching on soon enough. Thank you.
September 21, 2008.

Did you replace the thermostat? If not do so

Try bleeding it-don't work get it block and pressure tested


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

Sep 21, 2008.