Inspection and Verification
Engine Cooling
Inspection and Verification
WARNING: Always allow the engine to cool before opening the cooling system. Do not unscrew the coolant pressure relief cap when the engine is operating or the cooling system is hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly. Failure to follow these instructions may result in serious personal injury.
NOTICE: The engine cooling system is filled with Motorcraft(R) Specialty Green Engine Coolant. Do not mix coolant types. Mixing coolant types degrades the corrosion protection of the coolant. Failure to follow these instructions may damage the engine or cooling system.
NOTICE: Always fill the cooling system with the manufacturer's specified coolant. If a non-specified coolant has been used the cooling system must be chemically flushed. Refer to Cooling System Flushing Cooling System Flushing. Failure to follow these instructions may damage the engine or cooling system.
NOTICE: Genuine Mazda(R) Extended Life Coolant and Motorcraft(R) Specialty Green Engine Coolant are very sensitive to light. Do NOT allow these products to be exposed to ANY LIGHT for more than a day or two. Extended light exposure causes these products to degrade.
NOTE: Vehicles have the pressure relief cap on the degas bottle and no radiator cap.
1. Verify the customer concern.
2. Visually check the engine coolant level at the degas bottle when the system is cold.
3. Make sure the pressure relief cap is installed correctly.
4. Record any cooling system DTCs retrieved. Refer to the PCM DTC Chart for DTC descriptions. Diagnostic Trouble Code Tests and Associated Procedures
5. NOTE: Take note of any coolant odor or steam coming from cooling system components.
If the system coolant is filled correctly and no DTCs associated with fail-safe cooling are retrieved, verify the customer's concern by operating the engine to duplicate the condition.
6. NOTE: For the coolant flow diagrams, refer to Engine Cooling Description and Operation in the Description and Operation.
Visually inspect for obvious signs of any mechanical or electrical concerns damage.
Visual Inspection Chart
7. If the inspection reveals an obvious concern that can be readily identified, repair it as necessary. Test the system for normal operation.
8. NOTICE: The engine cooling system is filled with Motorcraft(R) Specialty Green Engine Coolant. Do not mix coolant types. Mixing coolant types degrades the corrosion protection of the coolant. Failure to follow these instructions may damage the engine or cooling system.
NOTICE: Genuine Mazda(R) Extended Life Coolant and Motorcraft(R) Specialty Green Engine Coolant are very sensitive to light. Do NOT allow these products to be exposed to ANY LIGHT for more than a day or two. Extended light exposure causes these products to degrade.
Inspect the coolant condition in the following sequence:
1. Inspect the coolant color.
- If the coolant has a clear or pale green color, this indicates higher water content than required. Test the engine coolant freezing point range with the Coolant/Battery Refractometer. The freezing point should be in the range -45°C to -23°C (-49°F to -9°F). If the vehicle is driven in cold climates less than -36°C (-33°F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Recommended coolant concentration is 50/50 coolant to distilled water.
- Reddish brown particles indicate that rust may be present in the cooling system. Flush the system and refill with the correct mixture of distilled water and the correct engine coolant.
- An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For information on engine diagnosis, refer to Engine System - General Information Testing and Inspection.
- A milky 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. Refer to Engine System - General Information Testing and Inspection. Component Tests and General Diagnostics
- 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 leaky radiator. Pressure test the cooling system. Refer to the Component Tests. Component Tests and General Diagnostics
2. If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Coolant/Battery Refractometer. The freezing point should be in the range -45°C to -23°C (-49°F to -9°F). If the vehicle is driven in cold climates less than -36°C (-33°F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Recommended coolant concentration is 50/50 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 undiluted 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.
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.
10. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
11. NOTE: The Vehicle Communication Module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to Module Communications Network Testing and Inspection, No Power To The Scan Tool, to diagnose no power to the scan tool.
12. If the scan tool does not communicate with the vehicle:
- verify the ignition key is in the ON position.
- verify the scan tool operation with a known good vehicle.
- refer to Module Communications Network Testing and Inspection to diagnose no response from the PCM.
13. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Module Communications Network Testing and Inspection.
- If the network test passes, retrieve and record continuous memory DTCs.
14. Clear the continuous DTCs and carry out the self-test diagnostics PCM.
15. If the DTCs recovered are related to the concern, go to the PCM DTC Chart. Diagnostic Trouble Code Tests and Associated Procedures
For all other PCM DTCs, refer to Electronic Engine Controls - Testing and Inspection.
16. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures