How to bleed a cooling system

• Why you need to do it:

  When you drain a cooling system or add a lot of new coolant, air can get trapped, causing air pockets in the radiator, hoses, and engine block. 
• How to do it:

  1. Start with the engine cold, cap off. 
  2. Turn the vehicle's heater: to full heat. 
  3. Start the engine: and allow it to warm up. 
  4. Gently rev the engine: to about 3,000 RPM. 
  5. Watch for air bubbles: to come out of the system. 
  6. Continue this process: until no more bubbles appear. 
  7. Add more coolant: to the reservoir as needed to maintain the level. 
  8. Once all air is out, turn off the engine, and install the radiator cap.