Engine Cooling System: Diagnosis Ford Taurus VI

Inspection and Verification

Note. The engine cooling system is filled with Motorcraft® Specialty Green Engine Coolant. Mixing coolant types degrades the corrosion protection of Motorcraft® Specialty Green Engine Coolant. Do not mix coolant types. Failure to follow these instructions may result in engine or cooling system damage.

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»(ref-355745-S25324354072010012800000) for DTC descriptions.
5. 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. Inspect to determine if any of the following mechanical or electrical concerns apply. VISUAL INSPECTION CHART Mechanical Electrical Leaks or weeps at: Hoses Tubes Clamp joints Gaskets O-rings Thermostat housing Radiator Pressure relief cap Coolant pump weep hole (LH side of block) Heater core (wet floor or coolant odor in vehicle) Degas bottle Cylinder block core plugs Cylinder head core plugs Block heater (if equipped) Turbochargers (if equipped) Inoperative or damaged: Electric cooling fan Wiring, connectors, relays or modules Cylinder Head Temperature (CHT) sensor Vehicle Speed Sensor (VSS) VISUAL INSPECTION CHART Mechanical Electrical Cracked or damaged: Hoses Tubes Hose clamps Thermostat housing Radiator Pressure relief cap Cooling fan Degas bottle Cylinder block core plugs Cylinder head core plugs Block heater (if equipped) Turbochargers (if equipped) Restricted airflow through the A/C condenser/radiator Excessive white or light gray exhaust smoke (may have burnt coolant odor) Coolant in engine oil Engine oil in coolant Engine vent hose check valve installed correctly
7. If the inspection reveals an obvious concern that can be readily identified, repair it as necessary. Test the system for normal operation.
8. Inspect the coolant condition in the following sequence: Inspect the coolant color. If Motorcraft® Specialty Green Engine Coolant has a clear or pale 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 (-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 coolant to distilled water. NOTE: If stop leak pellets are used, darkening of the coolant will occur. Dark could indicate a commercially available stop leak may have been used. Flush the system and refill with the correct mixture of distilled water and the correct engine coolant. 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»(ref-355700) . A milky brown color may indicate that engine oil is entering the cooling system. Pressure test the cooling system. Refer to «COMPONENT TESTS»(ref-355745-S37516114672010012800000) . If engine oil is suspected, the cause of the leak may be internal to the engine. Refer to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) . 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 (-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 ethylene glycol to distilled water. Maximum coolant concentration is 60/40 for cold weather areas. Minimum coolant concentration is 40/60 for warm weather areas. 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. If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
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 . refer to «MODULE COMMUNICATIONS NETWORK»(ref-355713) , 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»(ref-355713) 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»(ref-355713) . 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 PCM.
15. If the DTCs recovered are related to the concern, go to the «PCM DTC CHART»(ref-355745-S25324354072010012800000) . For all other DTCs, refer to «MULTIFUNCTION ELECTRONIC MODULES»(ref-355714) .
16. If no DTCs related to the concern are retrieved, GO to «SYMPTOM CHART»(ref-355745-S10840056882010012800000) .

PCM DTC Chart

PCM DTC CHART

Symptom Chart

SYMPTOM CHART

PINPOINT TEST A: LOSS OF COOLANT

1. A1 CARRY OUT INSPECTION AND VERIFICATION Carry out the «Inspection and Verification»(ref-355745-S07663518652010012800000) . Were any concerns found? Yes : REPAIR as needed. TEST the system for normal operation. No : GO to A2 .
2. A2 CHECK THE ENGINE COOLANT LEVEL NOTE: Allow the engine to cool before checking the engine coolant level. Ignition OFF. Visually inspect the engine coolant level at the degas bottle. Is the engine coolant level within specifications? Yes : GO to A3 . No : ADJUST the engine coolant level as necessary. GO to A3 .
3. A3 PRESSURE TEST THE ENGINE COOLING SYSTEM Pressure test the engine cooling system. Refer to «COMPONENT TESTS, COOLING SYSTEM PRESSURE TEST»(ref-355745-S17653013942010012800000) . Does the engine cooling system leak? Yes : REPAIR or INSTALL new components. TEST the system for normal operation. No : GO to A4 .
4. A4 CHECK THE ENGINE COOLANT FOR AN INTERNAL LEAK Inspect the engine coolant in the degas bottle for signs of engine oil. Is engine oil evident in the coolant? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : GO to A5 .
5. A5 CHECK THE ENGINE OIL FOR COOLANT Remove the oil level indicator from the engine. Is coolant evident in the oil? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : GO to A6 .
6. A6 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES NOTE: Use U-View® Combustion Leak Tester, part No. 560000 or equivalent. Using a cooling system combustion gas leak tester, following the instructions supplied with the tester, check the coolant for combustion gases. Are combustion gases present? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : The cooling system is operational.

PINPOINT TEST B: THE ENGINE OVERHEATS

1. B1 CARRY OUT INSPECTION AND VERIFICATION Carry out the «Inspection and Verification»(ref-355745-S07663518652010012800000) . Were any concerns found? Yes : REPAIR as needed. TEST the system for normal operation. No : GO to B2 .
2. B2 CHECK FOR DTCs NOTE: Refer to the «INTRODUCTION - GASOLINE MODELS»(ref-355661) for correct scan tool hook-up procedure. Check for DTC P1285 or P1299. Is DTC P1285 or P1299 present? Yes : GO to B3 . No : Actual engine overheating has not been verified. CHECK the ECT gauge operation. REFER to «INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES»(ref-355718) . If any other DTCs are retrieved, REFER to the «INTRODUCTION - GASOLINE MODELS»(ref-355661) .
3. B3 CHECK FOR AN AIRFLOW OBSTRUCTION Check the radiator or A/C condenser for an external obstruction such as leaves or cardboard. Is an obstruction present? Yes : REMOVE the obstruction. TEST the system for normal operation. No : GO to B4 .
4. B4 CHECK THE ENGINE COOLANT LEVEL NOTE: Allow the engine to cool before checking the coolant level. Ignition OFF. Visually check the engine coolant level in the degas bottle. Is the engine coolant level within specification? Yes : GO to B5 . No : ADJUST the engine coolant level as necessary. GO to B5 .
5. B5 PRESSURE TEST THE ENGINE COOLING SYSTEM Pressure test the engine cooling system. Refer to «COMPONENT TESTS, COOLING SYSTEM PRESSURE TEST»(ref-355745-S17653013942010012800000) . Does the engine cooling system leak? Yes : REPAIR or INSTALL new components. TEST the system for normal operation. No : GO to B6 .
6. B6 CHECK THE ENGINE COOLANT FOR AN INTERNAL LEAK Inspect the engine coolant in the degas bottle for signs of engine oil. Is engine oil evident in the coolant? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : GO to B7 .
7. B7 CHECK THE ENGINE OIL FOR COOLANT Remove the oil level indicator from the engine. Is coolant evident in the oil? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : GO to B8 .
8. B8 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES NOTE: Use U-View® Combustion Leak Tester, part No. 560000 or equivalent. Using a cooling system combustion gas leak tester, following the instructions supplied with the tester, check the coolant for combustion gases. Are combustion gases present? Yes : GO to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) for engine diagnosis. No : GO to B9 .
9. B9 CHECK COOLANT CONDITION Check the coolant for dirt, rust or contamination and check the coolant concentration. Is the coolant condition OK? Yes : GO to B10 . No : FLUSH the engine cooling system. REFER to «COOLING SYSTEM FLUSHING»(ref-355745-S27873139982010012800000) . TEST the system for normal operation.
10. B10 CHECK THE ELECTRIC COOLING FAN OPERATION Start the engine. Place the climate control function selector in the MAX A/C position and the blower motor switch in the HI position. Did the electric cooling fan operate? Yes : GO to B11 . No : DIAGNOSE the electric cooling fan operation. REFER to «INTRODUCTION - GASOLINE MODELS»(ref-355661) .
11. B11 CHECK THE COOLANT PUMP OPERATION Start the engine. Allow the engine to run for 30 minutes. Place the climate control function selector in the MAX HEAT position. Feel the heater outlet hose. Is the heater outlet hose hot? Yes : GO to B12 . No : INSTALL a new coolant pump. TEST the system for normal operation.
12. B12 CHECK THE THERMOSTAT OPERATION Start the engine. Allow the engine to run for 30 minutes. Feel the lower radiator hose. Is the lower radiator hose hot? Yes : CHECK the engine coolant temperature gauge operation. REFER to «INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES»(ref-355718) . No : For 3.5L, GO to B13 . For 3.5L Gasoline Turbocharged Direct Injection (GTDI), GO to B14 .
13. B13 CHECK THE ENGINE VENT HOSE CHECK VALVE Disconnect the engine vent hose from the engine and degas bottle. Using a light, look inside the end of the vent hose that connects to the engine. A check valve should be installed 50 mm (1.96 in) from the end of the hose. Using regulated compressed air, confirm air flows freely from the engine end to the degas bottle end. Using regulated compressed air, confirm air does not flow from the degas bottle end to the engine end. Is the check valve installed in the vent hose and does air flow through in one direction and not the other? Yes : GO to B15 . No : INSTALL a new engine vent hose. TEST the system for normal operation.
14. B14 CHECK THE ENGINE VENT HOSE CHECK VALVE Disconnect the engine vent hose from the engine and degas bottle. Using a light, look inside the end of the vent hose that connects to the degas bottle. A check valve should be installed 100 mm (3.94 in) from the end of the hose. Using regulated compressed air, confirm air flows freely from the engine end to the degas bottle end. Using regulated compressed air, confirm air does not flow from the degas bottle end to the engine end. Is the check valve installed in the vent hose and does air flow through in one direction and not the other? Yes : GO to B15 . No : INSTALL a new engine vent hose. TEST the system for normal operation.
15. B15 VISUALLY INSPECT THE THERMOSTAT Carry out the «Thermostat Visual Inspection»(ref-355745-S17694183592010012800000) . Is the thermostat damaged? Yes : INSTALL a new thermostat. TEST the system for normal operation. No : INSTALL a new thermostat. TEST the system for normal operation. If the engine still overheats, INSTALL a new radiator. TEST the system for normal operation.

PINPOINT TEST C: THE ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURE

1. C1 CARRY OUT INSPECTION AND VERIFICATION Carry out the «Inspection and Verification»(ref-355745-S07663518652010012800000) . Were any concerns found? Yes : REPAIR as needed. TEST the system for normal operation. No : GO to C2 .
2. C2 CHECK FOR DTC P0125 or P0128 NOTE: Refer to the «INTRODUCTION - GASOLINE MODELS»(ref-355661) for correct scan tool hook-up procedure. Check for DTC P0125 or P0128. Is DTC P0125 or P0128 present? Yes : GO to C3 . No : The cooling system is operational. If an inoperative ECT gauge is suspected, CHECK the ECT gauge operation. REFER to «INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES»(ref-355718) . If an inoperative climate control system is suspected, CHECK the climate control system operation. REFER to «CLIMATE CONTROL SYSTEM - GENERAL INFORMATION AND DIAGNOSTICS»(ref-355703) . If any other DTCs are retrieved, REFER to the «INTRODUCTION - GASOLINE MODELS»(ref-355661) .
3. C3 CHECK THE ELECTRIC COOLING FAN OPERATION Allow the engine to cool. Make sure the A/C switch is OFF (if equipped). Start the engine. Check the electric cooling fan. Is the electric cooling fan on all the time? Yes : DIAGNOSE the electric cooling fan operation. REFER to the «INTRODUCTION - GASOLINE MODELS»(ref-355661) . No : GO to C4 .
4. C4 CHECK THE COOLANT LEVEL NOTE: Allow the engine to cool before checking the coolant level. Visually check the engine coolant level in the degas bottle. Is the engine coolant level within specification? Yes : INSTALL a new thermostat. TEST the system for normal operation. No : Go To «PINPOINT TEST A»(ref-355745-S42112848112010012800000) to diagnose a coolant leak.

Cooling System Pressure Test

Note. Vehicles have the pressure relief cap on the degas bottle and no radiator cap.

Scheme 2

1. Turn the engine OFF.
2. Check the engine coolant level. Adjust the coolant level as necessary.
3. Attach the Pressure Tester to the degas bottle nipple and overflow hose. Install a pressure test pump to the quick connect fitting of the test adapter.
4. Slowly depress the plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained. If the pressure reading exceeds the maximum cap pressure listed in the specifications table, install a new pressure relief cap.
5. If the system does not hold pressure, remove the pressure relief cap and wash in clean water to dislodge all the foreign material from the gasket. Check the sealing surface in the filler neck of the degas bottle for nicks or cuts. Install the pressure relief cap.
6. Pressurize the engine cooling system as described in Step 4 above. Observe the gauge reading for approximately 2 minutes. Pressure should not drop during this time. If the pressure drops within this time, inspect for leaks and repair as necessary.
7. If no leaks are found and the pressure drops. the pressure relief cap may be leaking. Install a new pressure relief cap and retest the system.
8. If no leaks are found after a new pressure relief cap is installed, and the pressure drops, the leak may be internal to the engine. Inspect the coolant for engine oil and the engine oil for coolant. Refer to «ENGINE SYSTEM - GENERAL INFORMATION»(ref-355700) to diagnose the engine.
9. Release the system pressure by loosening the pressure relief cap. Check the coolant level and adjust as necessary.

Thermostat Visual Inspection

1. Remove the thermostat.
2. Examine the thermostat for signs of damage including: Valve not fully seated (light visible through the valve) Foreign material lodged in the main valve Bent or broken frame or flange Bent or broken spring Bent or broken valve or valve stem Wax leaking from wax reservoir or a bulge in the reservoir Any other damage or distortion
3. If damage is found during the inspection, remove any foreign material or broken pieces and install a new thermostat.
4. If no damage is found during the inspection, continue troubleshooting the system concern. Go to the «SYMPTOM CHART»(ref-355745-S10840056882010012800000) for further instructions.

Radiator Leak Test, Removed From Vehicle

Note. Never leak test an aluminum radiator in the same water that copper/brass radiators are tested in. Flux and caustic cleaners may be present in the cleaning tank and they will damage aluminum radiators.

Note. Clean the radiator before leak testing to avoid contamination of tank.

1. Leak test the radiator in clean water with pressurized air to the maximum pressure listed in the «SPECIFICATIONS»(ref-355745-S06793816062010012800000) .