Engine Cooling — Symptom Chart

Flush the system and refill with the correct mixture of distilled water and Orange Antifreeze/Coolant Concentrated. REFER to: Cooling System Draining and Vacuum Filling .

An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For engine diagnosis, REFER to: appropriate Engine article. Flush the system and refill with the correct mixture of distilled water and Orange Antifreeze/Coolant Concentrated. REFER to: Cooling System Draining and Vacuum Filling .

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: appropriate Engine article. Flush the system and refill with the correct mixture of distilled water and Orange Antifreeze/Coolant Concentrated. REFER to: Cooling System Draining and Vacuum Filling .

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°C and -37°C (-30°F and -34°F). If the vehicle is driven in cold climates less than -37°C (-34°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°C to -37°C [-30°F to -34°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 Antifreeze/Coolant Concentrated 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.

9. If an obvious cause for an observed or reported concern is found, correct the cause and test the system for normal operation before proceeding to the next step.

DIAGNOSIS AND TESTING > ENGINE COOLING > SYMPTOM CHART

Diagnostics in this service information assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods .