When performing routine maintenance on a vehicle's liquid cooling system, a technician needs to drain, refill, and bleed the system. In what sequential order should the technician perform these maintenance steps?
- 1Allow the engine to cool completely before removing the radiator pressure cap.
- 2Open the radiator drain petcock to empty the spent coolant into a collection container.
- 3Close the drain petcock and pour a fresh 50/50 antifreeze and water mixture into the system.
- 4Run the engine with the cabin heater set to high to circulate coolant and bleed trapped air pockets.
Answer
The correct sequence is: allow the engine to cool completely before removing the cap, open the drain petcock to empty the old coolant, close the drain and refill with fresh 50/50 mixture, and finally run the engine with the heater on to bleed trapped air pockets.
Proper cooling system servicing follows an essential chronological order: first, allowing the engine to cool prevents burn hazards when opening the radiator cap; second, opening the drain petcock drains the old fluid; third, closing the drain allows refilling with fresh 50/50 mixture; and fourth, running the engine with the heater on circulates coolant through the open thermostat and heater core to purge trapped air pockets.
Step-by-Step Solution
Key Concept
Cooling System Service and Air Bleeding Procedure
Estimated Time:45s