Initial Inspection and Diagnostic Overview
Engine Cooling
Special Tool(s)
Inspection and Verification
WARNING: To avoid personal injury, do not unscrew the coolant pressure relief cap while the engine is operating or hot. The coolant system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly.
CAUTION: Check the coolant level, engine oil and transmission fluid, top off the coolant if needed. If there is engine coolant in the engine oil or transmission fluid, the cause must be corrected and oil/fluid changed or major component damage can occur.
CAUTION: Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Coolant VC-7-A (in Oregon VC-7 B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color). Always fill the cooling system with the same coolant that is present in the system. Do not mix coolant types.
1. Verify the customer concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of the mechanical or electrical concerns apply.
3. If the inspection reveals an obvious concern that can be readily identified, repair as necessary.
4. Inspect the coolant condition.
1 Inspect the coolant color.
^ If Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color) has a clear, light green or blue color, this indicates higher water content than required.
^ If Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color) has a clear or pale yellow color, this indicates higher water content than required.
^ Dark brown could indicate unauthorized stop leak may have been used. Use Motorcraft Cooling System Stop Leak Pellets VC-6 or equivalent meeting Ford specification ESE-M99B37-B5 except as noted in ES-F6SE-19A511-AA only.
- The addition of Motorcraft Cooling System Stop Leak Pellets, VC-6, darkens Motorcraft Premium Gold Engine Coolant from yellow to golden brown.
^ 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 water and Premium Engine Coolant or Premium Gold Engine Coolant.
^ An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system.
^ A milky brown color may indicate that either engine oil or transmission fluid is entering the cooling system. If transmission fluid is suspected, the cause may be a leaky radiator. Pressure test the cooling system. If engine oil is suspected, the cause of the leak may be internal to the engine.
^ If transmission fluid is contaminated with engine coolant, the cause may be a leaky radiator. Pressure test the system.
2 If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Battery/Anti-Freeze Tester. The freezing point should be in the range -23°C to -46°C (-10°F to -50°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.
^ Maximum coolant concentration is 60/40.
^ Minimum coolant concentration is 40/60.
3 Adjust coolant range and level if necessary:
^ If the coolant is low, add specified coolant mixture only.
^ If the engine coolant tests weak, add straight engine coolant until the readings are within acceptable levels.
^ If the engine coolant tests strong, remove some of the engine coolant and add water until the readings are within acceptable levels.
5. If the concern remains after the inspection, determine the symptom(s) and go to the Symptom Chart. Symptom Related Diagnostic Procedures