Inspection and Verification

If the system coolant is filled correctly and no Diagnostic Trouble Codes (DTCs) associated with overheating are retrieved, verify the customer concern by operating the engine to duplicate the condition.

Visual Inspection Chart 

1. Inspect the coolant color.
   • Change in color of coolant may indicate that incorrect coolant may have been added to the system. Use of incorrect coolant degrades the corrosion protection. The addition of Motorcraft® Premium Antifreeze/Coolant or Motorcraft® Specialty Green Engine Coolant to the Motorcraft® Yellow Antifreeze/Coolant may cause the color to appear light green. Addition of Motorcraft® Orange Antifreeze/Coolant may cause the color to appear light orange. The addition of Motorcraft® Premium Antifreeze/Coolant or Motorcraft® Specialty Green Engine Coolant to the Motorcraft® Yellow Antifreeze/Coolant may cause the color to appear light green to murky green-brown. The addition of Motorcraft® Gold Antifreeze/Coolant, however, may not change the color or appearance of yellow-colored coolants. Detection of contamination with Motorcraft® Gold Antifreeze/Coolant is determined by the presence of nitrite. If contamination with Motorcraft® Gold Antifreeze/Coolant is suspected, test the coolant with the 3-Way HD Antifreeze Coolant Test Kit. Follow the nitrite testing directions in the kit to determine if nitrite is present in the system. If nitrite is present, flush the system and refill with the correct mixture of distilled water and the relevant Motorcraft® Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .
   • A darker yellow with the presence of debris could indicate a commercially available stop leak may have been used and could result in loss of coolant flow to critical parts of the engine. If sediment is present, flush the system and refill with the correct mixture of distilled water and Motorcraft® Yellow Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .
   • A light or reddish brown color indicates that rust may be present in the cooling system. Flush the system and refill with the correct mixture of distilled water and Motorcraft® Yellow Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .
   • An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For engine diagnosis, REFER to: Engine . Flush the system and refill with the correct mixture of distilled water and Motorcraft® Yellow Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .
   • A milky brown color may indicate that engine oil is entering the cooling system. Pressure test the cooling system. Refer to Component Tests  . If engine oil is suspected, the cause of the leak may be internal to the engine. For engine diagnosis, REFER to: Engine . Flush the system and refill with the correct mixture of distilled water and Motorcraft® Yellow Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .
   • A red, orange or light green colored sheen on top of the coolant may indicate that transmission fluid is entering the cooling system. The cause may be a internal leak in the radiator. Pressure test the cooling system. Refer to the Component Tests  . Flush the system and refill with the correct mixture of distilled water and Motorcraft® Yellow Concentrated Antifreeze/Coolant. REFER to: Engine Cooling System Flushing .

2. If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Coolant/Battery Refractometer. Maintain the coolant concentration within 48% to 50%, which equates to a freeze point between -34 deg.C and -37 deg.C (-30 deg.F and -34 deg.F). If the vehicle is driven in cold climates less than -37 deg.C (-34 deg.F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Recommended coolant concentration is 48/52 to 50/50 (freeze protection -34 deg.C to -37 deg.C [-30 deg.F to -34 deg.F]) engine coolant to distilled water.
   • Maximum coolant concentration is 60/40 for cold weather areas.
   • Minimum coolant concentration is 40/60 for warm weather areas.

3. Adjust coolant range and level if necessary:
   • If coolant is low, add specified coolant mixture only.
   • If the engine coolant tests too weak, remove some of the engine coolant and add Motorcraft® Orange Concentrated Antifreeze/Coolant until the readings are within acceptable levels.
   • If the engine coolant tests strong, remove some of the engine coolant and add distilled water until the readings are within acceptable levels.