Engine Cooling - Inspection/Verification
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ENGINE COOLING INSPECTION AND VERIFICATION - HYBRID
NOTE:See the Tribute Wiring Diagram for schematic information.
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.
CAUTION:The engine cooling system is filled with extended life engine coolant. Mixing coolant types degrades the corrosion protection of the coolant.
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 or coolant expansion tank when the system is cold.
3. Make sure the pressure relief cap is installed correctly.
4. Record any cooling system DTCs retrieved. See -- Engine Cooling - PCM DTC Chart for DTC descriptions.
5. If the system coolant is filled correctly and no DTCs associated with fail-safe cooling are retrieved, verify the customer concern by operating the engine to duplicate the condition.
NOTE:Take note of any coolant odor or steam coming from cooling system components.
6. Inspect to determine if any of the following mechanical or electrical concerns apply.
NOTE:For coolant flow diagrams, see - Engine Cooling Description And Operation
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.
NOTE:If Cooling System Stop Leak Pellets are used, darkening of the engine coolant from yellow to golden tan will occur.
8. Inspect the coolant condition.
a. Inspect the coolant color.
i. If the engine coolant has a clear or pale yellow color, this indicates higher water content than required. Test the engine coolant freezing point range with the Battery/Anti-Freeze Tester. The freezing point should be in the range -45°C to -23°C (-50°F to -10°F). If the vehicle is driven in cold climates less than -36°C (-34°F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Recommended coolant concentration is 50/50 Mazda Premium Engine Coolant of the type originally equipped in the vehicle to distilled water.
ii. A pale green color indicates incorrect coolant (green in color) may have been added to the system. Use of incorrect (green in color) coolant degrades the corrosion protection of engine coolant. Flush the system and refill with the correct mixture of distilled water and engine coolant.
iii. Dark brown could indicate a commercially available stop leak may have been used. Flush the system and refill with the correct mixture of distilled water and engine coolant.
iv. 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 engine coolant.
v. An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For information on engine diagnosis, see - Symptom Troubleshooting Chart - Engine.
vi. A milky brown color may indicate that engine oil is entering the cooling system. Pressure test the cooling system. See component tests in Cooling System. If engine oil is suspected, the cause of the leak may be internal to the engine. See - Symptom Troubleshooting Chart - Engine.
b. 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 -45°C to -23°C (-50°F to -10°F). If the vehicle is driven in cold climates less than -36°C (-34°F), it may be necessary to increase the coolant concentration to get adequate freeze protection. Recommended coolant concentration is 50/50 Mazda Premium Engine Coolant of the type originally equipped in the vehicle to distilled water.
i. Maximum coolant concentration is 60/40 for cold weather areas.
ii. Minimum coolant concentration is 40/60 for warm weather areas.
c. Adjust coolant range and level if necessary:
i. If coolant is low, add specified coolant mixture only.
ii. 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.
iii. 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. If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
NOTE:Make sure to use the latest scan tool software release.
11. 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.
- See - Communications Network - Troubleshooting, 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.
- See - Communications Network - Troubleshooting, 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, see - Communications Network - Troubleshooting.
- If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).
14. Clear the continuous DTCs and carry out the self-test diagnostics for the PCM.
15. If the DTCs recovered are related to the concern, see -- Engine Cooling - PCM DTC Chart. For all other DTCs, see - Engine B, C And U Codes - DTC Chart.
16. If no DTCs related to the concern are retrieved, see -- Symptom Troubleshooting Chart - Engine Cooling.