Engine Cooling System - 2.0L: Diagnosis Ford C-MAX II

DTC Chart

Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices.

REFER to: DIAGNOSTIC METHODS .

PCM DTC Chart

Inspection and Verification

REFER to: ENGINE COOLING SYSTEM HEALTH AND SAFETY PRECAUTIONS .

Note. The engine cooling system is filled with Motorcraft® Orange Antifreeze/Coolant. Always fill the cooling system with the manufacturer's specified coolant. Chemically flush the cooling system if a non-specified coolant has been used. Failure to follow these instructions may damage the engine or cooling system.

Note. During normal vehicle operation, Motorcraft® Orange Antifreeze/Coolant may change color from orange to pink or light red. As long as the engine coolant is clear and uncontaminated, this color change does not indicate the engine coolant has degraded nor does it require the engine coolant to be drained, the system to be flushed, or the engine coolant to be replaced.

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 Diagnostic Trouble Codes (DTCs) retrieved. Refer to the «PCM DTC CHART»(ref-635217-S03061584272014070200000) for DTC descriptions.
5. NOTE: Take note of any coolant odor or steam coming from cooling system components. If the system coolant is filled correctly and no Diagnostic Trouble Codes (DTCs) associated with fail-safe cooling are retrieved, verify the customer concern by operating the engine to duplicate the condition.
6. Visually inspect for obvious signs of any mechanical or electrical damage. VISUAL INSPECTION DESCRIPTIONS Mechanical Electrical Leaks or weeps at: Inoperative or damaged: Hoses Tubes Hose clamps Engine gaskets (may leak internally or externally) Thermostat housing Radiator Pressure relief cap Electric coolant pump Heater core (wet floor or coolant odor in vehicle) Degas bottle Cylinder block core plugs Cylinder head core plugs Block heater (if equipped) Engine coolant outlet connector adapter Cylinder block coolant pump hole cover Exhaust manifold heat recovery tube HEV Heater coolant temperature ( ECT ) sensor Auxiliary coolant pump - PHEV 3-way coolant valve - PHEV PTC heater - PHEV Electric coolant pump Electric cooling fan Wiring, connectors, relays or modules CHT sensor Vehicle Speed Sensor (VSS) Heater coolant temperature ( ECT ) sensor Auxiliary coolant pump - PHEV 3-way coolant valve - PHEV Cracked or damaged: Hoses Tubes Hose clamps Thermostat housing Radiator Pressure relief cap Cooling fan Electric coolant pump Degas bottle Cylinder block core plugs Cylinder head core plugs Block heater (if equipped) Engine coolant outlet connector adapter Cylinder block coolant pump hole cover Exhaust manifold heat recovery tube Heater coolant temperature ( ECT ) sensor Auxiliary coolant pump - PHEV 3-way coolant valve - PHEV PTC heater - PHEV 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
7. If the inspection reveals an obvious concern that can be readily identified, repair it as necessary.
8. Inspect the coolant condition. Inspect the coolant color. Discoloration may indicate that incorrect coolant may have been added to the system. Use of incorrect (green or yellow in color) coolant degrades the corrosion protection of Motorcraft® Orange Antifreeze/Coolant. Addition of Motorcraft® Specialty Green Engine Coolant may cause the color to appear a murky green-brown color. The addition of Motorcraft® Gold Antifreeze/Coolant, however, may not change the color or appearance of the orange colored coolant. Detection of contamination with Motorcraft® Gold Antifreeze/Coolant is determined by the presence of nitrite. If contamination with Motorcraft® Gold Antifreeze/Coolant is suspected, test the coolant with the 3-Way HD Antifreeze Coolant Test Kit. Follow the nitrite testing directions in the kit to determine if nitrite is present in the system. If nitrite is present, flush the system and refill with the correct mixture of distilled water and Motorcraft® Orange Antifreeze/Coolant Concentrated. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . A darker orange with the presence of debris could indicate a commercially available stop leak may have been used and could result in loss of coolant flow to critical parts of the engine. If sediment is present, flush the system and refill with the correct mixture of distilled water and Motorcraft® Orange Antifreeze/Coolant Concentrated. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . 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® Orange Antifreeze/Coolant Concentrated. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . An iridescent sheen on top of the coolant could indicate a trace of oil is entering the system. For engine diagnosis, REFER to: «ENGINE»(ref-635246-S38233782722014070200000) (303-00 Engine System - General Information, Diagnosis and Testing). Flush the system and refill with the correct mixture of distilled water and Motorcraft® Orange Antifreeze/Coolant Concentrated. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . A milky brown color may indicate that engine oil is entering the cooling system. Pressure test the cooling system. Refer to «COMPONENT TESTS»(ref-635217-S20782431402014070200000) . If engine oil is suspected, the cause of the leak may be internal to the engine. For engine diagnosis, REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . Flush the system and refill with the correct mixture of distilled water and Motorcraft® Orange Antifreeze/Coolant Concentrated. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . If the engine coolant appearance is acceptable, test the engine coolant freezing point range with the Coolant/Battery Refractometer. Maintain the coolant concentration within 48% to 50%, which equates to a freeze point between -34°C and -37°C (-30°F and -34°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. Recommended coolant concentration is 48/52 to 50/50 (freeze protection -34°C to -37°C [-30°F to - 34°F]) engine coolant 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 Motorcraft® Orange Antifreeze/Coolant Concentrated 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 no diagnostic trouble codes (DTCs) related to the concern are retrieved, GO to «SYMPTOM CHART»(ref-635217-S10082638092014070200000) . REFER to: «ENGINE COOLING»(ref-635217-S42560592502014070200000) .

Symptom Chart

Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices.

REFER to: DIAGNOSTIC METHODS .

PINPOINT TEST A: LOSS OF COOLANT

1. A1 PERFORM INSPECTION AND VERIFICATION Perform «INSPECTION AND VERIFICATION»(ref-635217-S22830120192014070200000) . Are any concerns present? Yes : REPAIR as needed. 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 «COOLING SYSTEM PRESSURE TEST»(ref-635217-S22634489712014070200000) . Does the engine cooling system leak externally? Yes : REPAIR or INSTALL new components. 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 : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . 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 : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . No : GO to A6
6. A6 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES NOTE: Use UView® Combustion Leak Tester part number UVU560000-R 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 : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . No : The cooling system is operational

Diagnostic Trouble Code (DTC) Fault Trigger Conditions

PINPOINT TEST B: THE ENGINE OVERHEATS

1. B1 PERFORM INSPECTION AND VERIFICATION Perform «INSPECTION AND VERIFICATION»(ref-635217-S22830120192014070200000) . Are any concerns present? Yes : REPAIR as needed. No : GO to B4
2. B2 CHECK FOR PCM (POWERTRAIN CONTROL MODULE) DTCS Ignition ON. Using a scan tool, perform PCM self-test. Is DTC P1285 or P1299 present? Yes : GO to B3 No : Actual engine overheating has not been verified. CHECK the engine coolant temperature gauge operation. REFER to: «INSTRUMENTATION, MESSAGE CENTER AND WARNING CHIMES»(ref-635200-S35230038012014070200000) . If any other PCM DTCs are retrieved, REFER to: «ELECTRONIC ENGINE CONTROLS - HYBRID ELECTRIC VEHICLE (HEV)»(ref-635205-S04377445452014070200000) . REFER to: «ELECTRONIC ENGINE CONTROLS - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635205-S24896621602014070200000) .
3. B3 CHECK FOR ACTIVE GRILL SHUDDER DTCS Review the PCM DTCs. Are any active grill shudder DTCs present? Yes : REFER to: «ACTIVE GRILLE SHUTTER»(ref-635237-S31265686792014070200000) . No : GO to B4
4. B4 CHECK FOR AN AIRFLOW OBSTRUCTION AND MISSING AIR DEFLECTORS NOTE: Verify no vehicle front end damage is present. Check the radiator or A/C condenser for an external obstruction such as leaves or cardboard and verify all air deflectors are present. Is an airflow obstruction present or air deflectors missing? Yes : REPAIR as necessary. No : GO to B5
5. B5 CHECK THE ENGINE COOLANT LEVEL Ignition OFF. Visually check the engine coolant level in the degas bottle. Is the engine coolant level within specification? Yes : GO to B6 No : ADJUST the engine coolant level as necessary. GO to B6
6. B6 PRESSURE TEST THE ENGINE COOLING SYSTEM Pressure test the engine cooling system. Refer to «COOLING SYSTEM PRESSURE TEST»(ref-635217-S22634489712014070200000) . Does the engine cooling system leak externally? Yes : REPAIR or INSTALL new components. No : GO to B7
7. B7 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 : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . No : GO to B8
8. B8 CHECK THE ENGINE OIL FOR COOLANT Remove the oil level indicator from the engine. Is coolant evident in the oil? Yes : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . No : GO to B9
9. B9 CHECK THE COOLING SYSTEM FOR COMBUSTION GASES NOTE: Use UView® Combustion Leak Tester part number UVU560000-R 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 : REFER to: «ENGINE»(ref-635246-S38233782722014070200000) . No : GO to B10
10. B10 CHECK COOLANT CONDITION Check the coolant for dirt, rust or contamination and check the coolant concentration. Is the coolant condition OK? Yes : GO to B11 No : FLUSH the engine cooling system. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) .
11. B11 CHECK THE ELECTRIC COOLING FAN OPERATION Turn the ignition key to the RUN position or, if equipped, press the START button to put the engine in RUN mode. Place the climate control function selector in the MAX A/C position and the blower motor switch in the HI position. Does the electric cooling fan operate? Yes : GO to B12 No : DIAGNOSE the electric cooling fan operation. Refer to «ENGINE CONTROLS - SYMPTOM CHARTS (HYBRID)»(ref-609000) .
12. B12 CHECK THE COOLANT PUMP OPERATION Turn the ignition key to the RUN position or, if equipped, press the START button with the transmission in park and the climate control system off. Press and hold the brake pedal for 10 seconds, then press the accelerator pedal to 100% for 10 seconds. 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 B13 No : BLEED the cooling system to remove any air. REFER to: «COOLING SYSTEM DRAINING, FILLING AND BLEEDING»(ref-635217-S18215536912014070200000) . REPEAT pinpoint test step. If the concern remains INSTALL a new coolant pump. REFER to: «COOLANT PUMP»(ref-635217-S06731968322014070200000) .
13. B13 CHECK THE THERMOSTAT OPERATION Turn the ignition key to the RUN position or, if equipped, press the START button with the transmission in park and the climate control system off. Press and hold the brake pedal for 10 seconds, then press the accelerator pedal to 100% for 10 seconds. Allow the engine to run for 30 minutes. Feel the radiator outlet hose. Is the radiator outlet hose hot? Yes : CHECK the temperature gauge operation. REFER to: «INSTRUMENTATION, MESSAGE CENTER AND WARNING CHIMES»(ref-635200-S35230038012014070200000) . No : GO to B14
14. B14 VISUALLY INSPECT THE THERMOSTAT Perform the «THERMOSTAT VISUAL INSPECTION»(ref-635217-S05494018112014070200000) in the Component Tests portion. Is the thermostat damaged? Yes : INSTALL a new thermostat. REFER to: «Thermostat»(ref-635217-S15394991022014070200000) . No : INSTALL a new thermostat. REFER to: «Thermostat»(ref-635217-S15394991022014070200000) . If the engine still overheats, INSTALL a new radiator. REFER to: «RADIATOR»(ref-635217-S35841042692014070200000) .

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

1. C1 PERFORM INSPECTION AND VERIFICATION Perform «INSPECTION AND VERIFICATION»(ref-635217-S22830120192014070200000) . Were any concerns found? Yes : REPAIR as needed. No : GO to C2
2. C2 CHECK FOR DTC P0125 OR P0128 Using a scan tool, perform the PCM self-test. Is DTC P0125 or P0128 present? Yes : For PHEV vehicles, GO to C3 For HEV vehicles, GO to C4 No : The cooling system is operational. If an inoperative temperature gauge is suspected, CHECK the temperature gauge operation. REFER to: «INSTRUMENTATION, MESSAGE CENTER AND WARNING CHIMES»(ref-635200-S35230038012014070200000) . If an inoperative climate control system is suspected, CHECK the climate control system operation. REFER to: «CLIMATE CONTROL SYSTEM»(ref-635194-S37604727682014070200000) . For all other PCM Diagnostic Trouble Codes (DTCs), REFER to: «ELECTRONIC ENGINE CONTROLS - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635205-S24896621602014070200000) .
3. C3 CHECK FOR DTC P2183, P2184, P2185, P2186, P2682, P2683 OR P26AB Using a scan tool, review the PCM DTCs. Is DTC P2183, P2184, P2185, P2186, P2682, P2683, or P26AB present? Yes : DIAGNOSE these PCM DTCs to address the P0125 or P0128. REFER to: «AUXILIARY CLIMATE CONTROL»(ref-635252-S22839688742014070200000) . No : GO to C4
4. C4 CHECK THE COOLANT LEVEL NOTE: Allow the engine to cool before checking the degas bottle. Visually check the engine coolant level in the degas bottle. Is the engine coolant level within specification? Yes : INSTALL a new thermostat. REFER to: «Thermostat»(ref-635217-S15394991022014070200000) . CLEAR the Diagnostic Trouble Codes (DTCs). If the DTC returns check for correct CHT sensor operation. No : GO to «PINPOINT TEST A»(ref-635217-S16549378262014070200000)

PINPOINT TEST D: THE ELECTRIC COOLANT PUMP IS INOPERATIVE OR DOES NOT OPERATE CORRECTLY

Refer to COOLING FAN for schematic and connector information.

Visual Inspection and Diagnostic Prechecks

1. Inspect the BJB fuse 2 (50A).
2. Inspect the BJB fuse 35 (10A).
3. Make sure the electric coolant pump electrical connector is not disconnected.

1. D1 RETRIEVE THE PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) Ignition ON. Using a scan tool, perform PCM self-test. Is DTC P26CA present? Yes : GO to D2 No : For Diagnostic Trouble Codes (DTCs) P26D0, P26D1 or P26D3, GO to D5 For DTC U019F, GO to D7 For all other PCM Diagnostic Trouble Codes (DTCs), REFER to: «ELECTRONIC ENGINE CONTROLS - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635205-S24896621602014070200000) .
2. D2 RETRIEVE ALL CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS) IN ALL MODULES Using a diagnostic scan tool, perform a All Continuous Memory Diagnostic Trouble Codes (CMDTCs) self test. Is DTC P0562, U3003:1C, U3003:16 present in more than one module? Yes : DIAGNOSE the charging system. For HEV vehicles, REFER to: «DIRECT CURRENT/DIRECT CURRENT (DC/DC) CONVERTER CONTROL MODULE - HYBRID ELECTRIC VEHICLE (HEV)»(ref-635197-S04794900842014070200000) . For PHEV vehicles, REFER to: «DIRECT CURRENT/DIRECT CURRENT (DC/DC) CONVERTER CONTROL MODULE - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635197-S24090710322014070200000) . No : GO to D3
3. D3 CHECK THE ELECTRIC COOLANT PUMP CONTROL CIRCUIT VOLTAGE Ignition OFF. Disconnect: Electric Coolant Pump C1812. Ignition ON. Measure: Positive Lead Measurement/Action Negative Lead C1812-3 Ground Is the voltage greater than 11 volts? Yes : GO to D4 No : VERIFY BJB fuse 35 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the «OEM WIRING DIAGRAMS»(ref-647773) to identify the cause of the short circuit.
4. D4 CHECK THE ELECTRIC COOLANT PUMP GROUND CIRCUIT FOR AN OPEN Ignition OFF. Measure: Positive Lead Measurement/Action Negative Lead C1812-1 Ground Is the resistance less than 3 ohms? Yes : INSTALL a new electric coolant pump. CLEAR the Diagnostic Trouble Codes (DTCs). TEST the system for normal operation. If DTC P26CA resets, install a new PCM . No : REPAIR the circuit.
5. D5 CHECK THE ELECTRIC COOLANT PUMP SUPPLY CIRCUIT VOLTAGE Ignition OFF. Disconnect: Electric Coolant Pump C1812. Ignition ON. Measure: Positive Lead Measurement/Action Negative Lead C1812-2 Ground Is the voltage greater than 11 volts? Yes : GO to D6 No : VERIFY BJB fuse 2 (50A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the «OEM WIRING DIAGRAMS»(ref-647773) to identify the cause of the short circuit.
6. D6 CHECK THE ELECTRIC COOLANT PUMP GROUND CIRCUIT FOR AN OPEN Ignition OFF. Measure: Positive Lead Measurement/Action Negative Lead C1812-1 Ground Is the resistance less than 3 ohms? Yes : INSTALL a new electric coolant pump. CLEAR the Diagnostic Trouble Codes (DTCs). TEST the system for normal operation. If DTC P26D0, P26D1 or P26D3 resets, install a new PCM . No : REPAIR the circuit.
7. D7 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN Ignition OFF. Disconnect: Electric Coolant Pump C1812. Disconnect: PCM C175E. Measure: Positive Lead Measurement/Action Negative Lead C1812-4 C175E-39 Is the resistance less than 3 ohms? Yes : GO to D8 No : REPAIR the circuit.
8. D8 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) FOR A SHORT TO VOLTAGE Ignition ON. Measure: Positive Lead Measurement/Action Negative Lead C1812-4 Ground Is any voltage present? Yes : GO to D9 No : GO to D10
9. D9 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) FOR A SHORT TO VOLTAGE WITH THE ACTIVE GRILLE SHUTTER ACTUATOR DISCONNECTED Ignition OFF. Disconnect: Active Grille Shutter Actuator C1651. Ignition ON. Measure: Positive Lead Measurement/Action Negative Lead C1812-4 Ground Is any voltage present? Yes : REPAIR the circuit. No : INSTALL a new active grille shutter. REFER to: «ACTIVE GRILLE SHUTTER»(ref-635237-S38052633542014070200000) .
10. D10 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Measure: Positive Lead Measurement/Action Negative Lead C1812-4 Ground Is the resistance greater than 10, 000 ohms? Yes : INSTALL a new electric coolant pump. CLEAR the Diagnostic Trouble Codes (DTCs). TEST the system for normal operation. If DTC U019F resets, install a new PCM . No : GO to D11
11. D11 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND WITH THE ACTIVE GRILLE SHUTTER ACTUATOR DISCONNECTED Disconnect: Active Grille Shutter Actuator C1651. Measure: Positive Lead Measurement/Action Negative Lead C1812-4 Ground Is the resistance greater than 10, 000 ohms? Yes : INSTALL a new active grille shutter. REFER to: «ACTIVE GRILLE SHUTTER»(ref-635237-S38052633542014070200000) . No : REPAIR the circuit.

Cooling System Pressure Test

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

Scheme 9

1. Turn the engine OFF.
2. Check the engine coolant and adjust as necessary.
3. REFER to: «AIR CLEANER OUTLET PIPE»(ref-635250-S38239475042014070200000) . NOTE: Be prepared to contain escaping fluid.
4. Attach the D-Gas Adapter to the EGR valve and the disconnected hose. Install a pressure test pump to the quick connect fitting of the test adapter.
5. NOTE: Do not pressurize the cooling system beyond 172 kPa (25 psi) or cooling system components may be damaged. NOTE: If the plunger of the pressure tester is pressed too fast, an erroneous pressure reading results. Slowly press 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 155 kPa (22.5 psi), install a new pressure relief cap.
6. 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.
7. Pressurize the engine cooling system as described in Step 5 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.
8. 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.
9. 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»(ref-635246-S38233782722014070200000) to diagnose the engine.
10. 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 Wax leaking from wax reservoir or a bulge in the reservoir Any other damage or distortion
3. NOTE: If no damage is found during the inspection, do not attempt to open the thermostat using hot water or other heat sources. This method is not an accurate means to test the function of the thermostat and may damage the thermostat.

If damage is found during the inspection, remove any foreign material or broken pieces and install a new thermostat.

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 air pressurized to 138 kPa (20 psi).