ENGINE OVER TEMPERATURE (OVERHEAT) - Main 12 Causes of Overheating
EF & EC-7226spec tableMain 12 Causes of Overheating
OFF
Step1
Inspection itemBlocked radiator; Blocked condenser; Blocked radiator grille; Blocked bumper
EquipmentVisual
StandardNo blocking
Reference page—
OFF
Step2
Inspection itemCoolant mixture
EquipmentCoolant tester
Standard50 - 50% coolant mixture
Reference pageSee "RECOMMENDED FLUIDS AND LUBRICANTS" in MA section.
OFF
Step3
Inspection itemCoolant level
EquipmentVisual
StandardCoolant up to MAX level in reservoir tank and radiator filler neck
Reference pageSee "Changing Engine Coolant", "ENGINE MAINTENANCE" in MA section.
OFF
Step4
Inspection itemRadiator cap
EquipmentPressure tester
Standard59 - 98 kPa (0.59 - 0.98 bar, 0.6 - 1.0 kg/cm², 9 - 14 psi) (Limit)
Reference pageSee "System Check", "ENGINE COOLING SYSTEM" in LC section.
ON*2
Step5
Inspection itemCoolant leaks
EquipmentVisual
StandardNo leaks
Reference pageSee "System Check", "ENGINE COOLING SYSTEM" in LC section.
ON*2
Step6
Inspection itemThermostat
EquipmentTouch the upper and lower radiator hoses
StandardBoth hoses should be hot
Reference pageSee "Thermostat" and "Radiator", "ENGINE COOLING SYSTEM" in LC section.
ON*1
Step7
Inspection itemCooling fan
EquipmentCONSULT-II
StandardOperating
Reference pageSee "TROUBLE DIAGNOSIS FOR OVERHEAT".
OFF
Step8
Inspection itemCombustion gas leak
EquipmentColor checker chemical tester 4 Gas analyzer
StandardNegative
Reference page—
ON*3
Step9
Inspection itemCoolant temperature gauge
EquipmentVisual
StandardGauge less than 3/4 when driving
Reference page—
ON*3
Step9
Inspection itemCoolant overflow to reservoir tank
EquipmentVisual
StandardNo overflow during driving and idling
Reference pageSee "Changing Engine Coolant", "ENGINE MAINTENANCE" in MA section.
OFF*4
Step10
Inspection itemCoolant return from reservoir tank to radiator
EquipmentVisual
StandardShould be initial level in reservoir tank
Reference pageSee "ENGINE MAINTENANCE" in MA section.
OFF
Step11
Inspection itemCylinder head
EquipmentStraight gauge feeler gauge
Standard0.1 mm (0.004 in) Maximum distortion (warping)
Reference pageSee "Inspection", "CYLINDER HEAD" in EM section.
OFF
Step12
Inspection itemCylinder block and pistons
EquipmentVisual
StandardNo scuffing on cylinder walls or piston
Reference pageSee "Inspection", "CYLINDER BLOCK" in EM section.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to "OVERHEATING CAUSE ANALYSIS" in LC section.