No.17 Cooling System Concerns-Overheating - Mazda CX-7 2007 Workshop Manual

SYMPTOM TROUBLESHOOTING [L3 WITH TC]
NO.17 COOLING SYSTEM CONCERNS-OVERHEATING[L3 WITH TC]
17 COOLING SYSTEM CONCERNS -OVERHEATING
DESCRIPTION Engine runs at higher than normal temperature/overheats.
• Improper coolant level
• Blown fuse
• Coolant leakage (engine internal, turbocharger, external)
• Excessive A/C system pressure
• A/C system operation is improper
• Improper water/anti-freeze mixture
• Fans reverse rotation
• Poor radiator condition
POSSIBLE CAUSE
• Thermostat malfunction
• Radiator hose damage
• Cooling fan inoperative
• Condenser fan inoperative
• Improper or damaged radiator cap
• Coolant overflow system malfunction
• Improper drive belt tension
• Drive belt damage
Diagnostic procedure
STEP INSPECTION
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
• Fan rotation direction
• Fuses
Are all items normal?
2 Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position
(Engine off).
Retrieve any DTCs.
Is there any DTCs displayed?
3 Perform the KOEO and KOER self-test function
using the M-MDS.
(See01-02-10 KOEO/KOER SELF TEST[L3
WITH TC].)
Is there any DTCs displayed?
4 Start the engine and run it at idle speed.
Turn the A/C switch off.
Does the A/C compressor disengaged?
5 Perform the Cooling Fan Control System
Operation Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the cooling fan system operate properly?
6 Is the drive belt normal?
7 Is there any leakage around heater unit in
passenger compartment?
8 Is there any leakage at coolant hoses and/or
radiator?
01-03–60
RESULTS
Yes Go to the next step.
No Service if necessary.
Repeat Step 1.Service if necessary.
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to the next step.
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed: Go to the next step.
Yes Go to the next step.
No Go to symptom troubleshooting "NO.24 A/C ALWAYS
ON OR A/C COMPRESSOR RUNS CONTINUOUSLY."
(See01-03-69 NO.24 A/C IS ALWAYS ON OR A/C
COMPRESSOR RUNS CONTINUOUSLY[L3 WITH
TC].)
Yes Go to the next step.
No Repair or replace malfunctioning part, according to
inspection results.
Yes Go to the next step.
No Replace the drive belt.
Yes Inspect and service heater unit for leakage.
No Go to the next step.
Yes Replace the malfunctioning part.
No Go to the next step.
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