NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.3 DISI Turbo]

17	COOLING SYSTEM CONCERNS—OVERHEATING
DESCRIPTION	• Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Improper coolant level • Blown fuse • Coolant leakage (engine internal, turbocharger, external) • Excessive A/C system pressure • Improper operation of A/C system • Improper water/anti-freeze mixture • Fans reverse rotation • Poor radiator condition • Thermostat malfunction • Radiator hose damage • Cooling fan inoperative • Improper or damaged radiator cap • Coolant overflow system malfunction • Improper drive belt tension • Drive belt damage • ECT sensor or related circuit malfunction • Instrument cluster malfunction

COOLING SYSTEM CONCERNS—OVERHEATING

DESCRIPTION

• Engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

• Improper coolant level

• Blown fuse

• Coolant leakage (engine internal, turbocharger, external)

• Excessive A/C system pressure

• Improper operation of A/C system

• Improper water/anti-freeze mixture

• Fans reverse rotation

• Poor radiator condition

• Thermostat malfunction

• Radiator hose damage

• Cooling fan inoperative

• Improper or damaged radiator cap

• Coolant overflow system malfunction

• Improper drive belt tension

• Drive belt damage

• ECT sensor or related circuit malfunction

• Instrument cluster malfunction

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the 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.
No	Go to the next step.
2	Switch the ignition to ON. Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.3 DISI Turbo].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 2.3 DISI Turbo].)
No	Go to the next step.
3	Perform the KOEO or KOER self test using the M-MDS. (See KOEO/KOER SELF TEST [MZR 2.3 DISI Turbo].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 2.3 DISI Turbo].)
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.
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 2.3 DISI Turbo].)
5	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.3 DISI Turbo].) Does the cooling fan system operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
6	Inspect the drive belt. (See DRIVE BELT INSPECTION [MZR 2.3 DISI Turbo].) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)
No	Go to the next step.
7	Inspect for leakage around heater unit in the passenger compartment. Is there any leakage?	Yes	Inspect the heater unit for leakage. Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
8	Inspect for leakage at the coolant hoses and/or radiator. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
9	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].) Inspect the thermostat. (See THERMOSTAT INSPECTION [MZR 2.3 DISI Turbo].) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)
No	Reinstall the thermostat, then go to the next step. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)
10	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.3 DISI Turbo].) Inspect for both ECT PID and temperature gauge readings. Does the ECT PID value accord with the engine coolant temperature indicator readings?	Yes	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.
No	If the low engine coolant temperature indicator light on the instrument cluster indicates turned off but the ECT PID value is not the same as the low engine coolant temperature indicator light condition: • Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 2.3 DISI Turbo].) • Replace the ECT sensor if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].) If the low engine coolant temperature indicator light indication on the instrument cluster illuminates but the ECT PID value is normal: • Inspect the instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.) • Replace the instrument cluster if necessary. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
11	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • 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, reprogram the PCM if a later calibration is available. Retest.

STEP

INSPECTION

RESULTS

ACTION

Inspect for the 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.

Go to the next step.

Switch the ignition to ON.

Retrieve any DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.3 DISI Turbo].)

Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [MZR 2.3 DISI Turbo].)

Go to the next step.

Perform the KOEO or KOER self test using the M-MDS.

(See KOEO/KOER SELF TEST [MZR 2.3 DISI Turbo].)

Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [MZR 2.3 DISI Turbo].)

Go to the next step.

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.

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 2.3 DISI Turbo].)

Perform the Cooling Fan Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.3 DISI Turbo].)

Does the cooling fan system operate properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Inspect the drive belt.

(See DRIVE BELT INSPECTION [MZR 2.3 DISI Turbo].)

Is there any malfunction?

Yes

Replace the drive belt.

(See DRIVE BELT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)

Go to the next step.

Inspect for leakage around heater unit in the passenger compartment.

Is there any leakage?

Yes

Inspect the heater unit for leakage.

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect for leakage at the coolant hoses and/or radiator.

Is there any leakage?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Cool down the engine.

Remove the thermostat.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)

Inspect the thermostat.

(See THERMOSTAT INSPECTION [MZR 2.3 DISI Turbo].)

Is there any malfunction?

Yes

Replace the thermostat.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)

Reinstall the thermostat, then go to the next step.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.3 DISI Turbo].)

Inspect for both ECT PID and temperature gauge readings.

Does the ECT PID value accord with the engine coolant temperature indicator readings?

Yes

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.

If the low engine coolant temperature indicator light on the instrument cluster indicates turned off but the ECT PID value is not the same as the low engine coolant temperature indicator light condition:

• Inspect the ECT sensor.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 2.3 DISI Turbo].)

• Replace the ECT sensor if necessary.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 2.3 DISI Turbo].)

If the low engine coolant temperature indicator light indication on the instrument cluster illuminates but the ECT PID value is normal:

• Inspect the instrument cluster.

(See INSTRUMENT CLUSTER INSPECTION.)

• Replace the instrument cluster if necessary.

(See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms.

• 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, reprogram the PCM if a later calibration is available. Retest.