NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.0 DISI]

id0103d5802300

17

COOLING SYSTEM CONCERNS—OVERHEATING

DESCRIPTION

•  Engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

•  Improper coolant level

•  Coolant leakage (engine internal, external)

•  Improper water/anti-freeze mixture

•  Poor radiator condition

•  Radiator hose damage

•  Improper or damaged radiator cap

•  Coolant overflow system malfunction

•  Fans reverse rotation

•  Blown fuse

•  PCM DTC is stored

•  Improper operation of A/C system

•  Cooling fan inoperative

•  Drive belt damage

•  Improper drive belt tension

•  Leakage around heater unit in passenger compartment

•  Leakage at coolant hoses and/or radiator

•  Thermostat malfunction

•  Improper indication of water temperature gauge

―  ECT sensor malfunction

―  Instrument cluster malfunction

•  Excessive A/C system pressure

17	COOLING SYSTEM CONCERNS—OVERHEATING
DESCRIPTION	• Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Improper coolant level • Coolant leakage (engine internal, external) • Improper water/anti-freeze mixture • Poor radiator condition • Radiator hose damage • Improper or damaged radiator cap • Coolant overflow system malfunction • Fans reverse rotation • Blown fuse • PCM DTC is stored • Improper operation of A/C system • Cooling fan inoperative • Drive belt damage • Improper drive belt tension • Leakage around heater unit in passenger compartment • Leakage at coolant hoses and/or radiator • Thermostat malfunction • Improper indication of water temperature gauge ― ECT sensor malfunction ― Instrument cluster malfunction • Excessive A/C system pressure

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for following: • Engine coolant level • Coolant leakage (around heater unit in passenger compartment, coolant hoses and/or radiator.) • Water and anti-freeze mixture • Radiator condition • Collapsed or restricted radiator hoses • Radiator pressure cap • Coolant overflow system • Fan rotational direction • Fuses Is there any malfunction?	Yes	Service if necessary. • Repeat this step.
1		No	Go to the next step.
2	Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 2.0 DISI].)
2		No	Go to the next step.
3	Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [MZR 2.0 DISI].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 2.0 DISI].)
3		No	Go to the next step.
4	Start the engine and run it at idle speed. Turn the A/C switch off. Does the A/C compressor disengaged?	Yes	Go to the next step.
4		No	Perform the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”. (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR 2.0 DISI].)
5	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Does the cooling fan control system operate properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	Inspect the drive belt. (See DRIVE BELT INSPECTION [MZR 2.0 DISI].) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [MZR 2.0 DISI].)
6		No	Go to the next step.
7	Inspect for leakage around heater unit in passenger compartment. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	Inspect for leakage at coolant hoses and/or radiator. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Compare the ECT PID and water temperature gauge readings. Is the ECT PID value same as water temperature gauge readings?	Yes	Go to the next step.
9		No	Inspect the water temperature gauge. (See INSTRUMENT CLUSTER INSPECTION.) • If there is any malfunction: ― Repair or replace the malfunctioning part according to the inspection results. • If there is no malfunction: ― Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 2.0 DISI].) ― Replace the ECT sensor if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)
10	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI].) Inspect the thermostat operation. (See THERMOSTAT INSPECTION [MZR 2.0 DISI].) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI].)
10		No	The engine coolant temperature and thermostat are normal. • Inspect the engine block for leakage or blockage. • Repair or replace the malfunctioning part according to the inspection results.
11	Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI].) • If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)