Heater Core Backflushing

Special Tool(s) 

Fig 1: Identifying Special Tools

Courtesy of FORD MOTOR CO.

Material 

WARNING: Never remove the pressure relief cap while the engine is operating or when the cooling system is hot. Failure to follow these instructions can result in damage to the cooling system or engine or personal injury. To avoid having scalding hot coolant or steam blow out of the degas bottle when removing the pressure relief cap, wait until the engine is cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, turn and remove the pressure relief cap (still with a cloth).
1. Once pressure is released, remove the pressure relief cap.
2. Partially drain the cooling system. Refer to COOLING SYSTEM DRAINING, FILLING AND BLEEDING  .
NOTE: Refer to the cooling system flusher manufacturer's operating instructions for particular vehicle hook-up.
3. Use an appropriate cooling system flusher to backflush the heater core. Use Motorcraft Premium Cooling System Flush VC-1 or equivalent meeting Ford specification ESR-M14P7-A. Flush with water thoroughly after using VC-1 or equivalent prior to refilling the cooling system
4. Fill and bleed the cooling system. Refer to COOLING SYSTEM DRAINING, FILLING AND BLEEDING  .