Initial Inspection and Diagnostic Overview
Inspection and VerificationWARNING: To avoid personal injury, do not unscrew the coolant pressure relief cap while the engine is operating or hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly.
CAUTION: Always fill the cooling system with the same coolant that is present in the system. Do not mix coolant types.
CAUTION: If there is engine coolant in the engine oil, the cause must be corrected and the oil changed or engine damage may occur.
CAUTION: If there is coolant in the transmission fluid, the cause must be corrected and the transmission fluid changed or transmission damage may occur.
1. Verify the customer's concern by operating the engine to duplicate the condition.
2. Inspect to determine if any of these mechanical or electrical concerns apply.
Visual Inspection Chart:
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 Gold Engine Coolant VC-7-A (in California, Oregon and New Mexico VC-7-B in Canada CVC-7-A) or equivalent (yellow color) meeting Ford specification WSS-M97B51-A1 has a clear or pale yellow color, this indicates higher water content than required.
^ Dark brown could indicate unauthorized Stopleak may have been used. Use Cooling System Stop Leak Pellets VC-6 or equivalent meeting Ford specification WSS-M99B37-B6.
^ 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 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. For additional information, refer to component tests. 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. For additional information, refer to the component tests.
2 If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the special tool. The freezing point should be in the range of 50°F to -10°F. If the vehicle is driven in cold climates (lower than -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 coolant is low, add specified coolant mixture only.
^ If the engine coolant tests too 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 distilled water until the readings are within acceptable levels.
5. If the concern remains after the inspection, determine the symptom(s). GO to Symptom Chart. Symptom Related Diagnostic Procedures