The 1998 Pontiac Sunfire came equipped from the factory with a phosphate-free, orange colored, anti-freeze/coolant to help prevent corrosion damage to aluminum components. This type of anti-freeze is prone to developing sludge and deposits that can clog narrow cooling passages and cause overheating or ineffective heater function. Switching to the typical poly-glycol based (green) antifreeze can be done safely if yearly cooling system maintenance is done. The average home mechanic can complete this task in just a couple of hours.
Instructions
- 1
Remove the radiator cap located on top of the coolant reservoir on the passenger-side fender-well in the engine compartment. Start the engine and turn on the heater. Allow the engine to run until it reaches operating temperature and the thermostat open. Both the upper and lower radiator hoses will be hot when the thermostat opens.
2Place a drain pan under the Sunfire below the right front corner of the radiator.Twist the drain valve on the bottom of the driver-side radiator tank counter-clockwise until coolant runs out of the valve. Drain the coolant into the drain pan.
3Pour the flush chemical into the coolant reservoir and then fill the cooling system with clean water. The Cooling system is filled through the coolant reservoir in the Sunfire. Start the engine and allow it to run for 15 minutes after the thermostat opens again. This will remove any residue of sludge built up by the orange coolant and suspend it in the water so it can be removed.
4Turn off the engine. Drain the cooling system again then fill the system with clean water and start the engine. Allow the clean water to circulate for 15 minutes and drain the system one final time.
5Turn off the engine. Fill the cooling system with clean anti-freeze mixed in a 50/50 ratio with clean water and start the engine. Allow the engine to run until the thermostat opens and add coolant to the reservoir until it is at the full mark embossed on the coolant reservoir. Reinstall the radiator cap.
