I just flushed the coolant on my Zetec last week. I had to do an extra good job because I changed over to Dex-Cool (SP?).
1. Drain old coolant
2. remove thermostat
3. assemble thermostat housing without a T-stat installed - hand tighten bolts
4. stick running hose into coolant resevoir (yes leave the drain plug open at the radiator)
5. start car & let the fresh water pump through the system and drain out the bottom - adjust flow from hose as needed. Continue for perhaps 5 to 10 minutes.
6. Turn off engine
7. Turn off hose
8. Allow water to drain from radiator until it stops flowing. Tighten the drain plug
9. Install new t-stat per instruction & tighten housing appropriately. (I modified & installed a 160 degree t-stat)
10. Add a bottle of water wetter and about 4 quarts of Dex-Cool.
11. Top off the system with distilled water to appropriate fill mark.
12. Go for a drive, watch temp gauge reach just barely into the normal range & needle stay at the low end while driving. Watch temp gauge reach mid point at loooooong stop lights or when driving REALLY hard, then drop down again under normal driving conditions.
13. Park the car in driveway, add more distilled water if needed, put hose & tools away.
14. Beer, shower, watch television with beer, beer, beer, and then sleep well.
