Engine Overheating

Procedure	Operation	Yes	No
Definition: Either of the following conditions indicate a probable engine overheat condition: the engine temperature indicator keeps ON; the engine temperature gauge is in the red (overheat) zone; engine coolant overflows from the surge tank onto the ground while the engine is running.
1	Check for coolant loss. Refer to Loss of Coolant . Is coolant loss discovered?	Go to Step 2.	Go to Step 3.
2	Add coolant to the system until the coolant reaches the specified level. Does the engine still overheat?	Go to Step 3.	The system is normal.
3	Check the surge tank hose for twisting or pinching, especially that at the radiator. Is the surge tank hose twisted or pinched?	Go to Step 4.	Go to Step 5.
4	1.Rearrange the hose to straighten the twist. 2.Replace the hose if necessary. Does the engine still overheat?	Go to Step 5.	The system is normal.
5	Check the radiator air seal or deflector for looseness, missing or damage. Is the radiator air seal or deflector loose, missing or damaged?	Go to Step 6.	Go to Step 7.
6	Repair the loose, missing or damaged radiator air seal or deflector. Does the engine still overheat?	Go to Step 7.	The system is normal.
7	Check the coolant concentration. Is the coolant concentration test result correct?	Go to Step 9.	Go to Step 8.
8	Replace the coolant if necessary. Does the engine still overheat?	Go to Step 9.	The system is normal.
9	Note: Use the correct pressure cap. Check the system for pressure loss. Does pressure loss exist?	Go to Step 10.	Go to Step 11.
10	Repair all leaks if necessary. Does the engine still overheat?	Go to Step 11.	The system is normal.
11	Check the engine coolant temperature sensor for faults. Does any engine coolant temperature sensor fault exist?	Go to Step 12.	Go to Step 13.
12	Replace the engine coolant temperature sensor.	Go to Step 13.	The system is normal.
13	Check the radiator for flow blockage or bent cooling fins. Does flow blockage or bent cooling fins exist?	Go to Step 14.	Go to Step 15.
14	1.Remove or relocate the aftermarket component that obstructs air flow to the radiator. 2.Clean the debris on the radiator core. Does the engine still overheat?	Go to Step 15.	The system is normal.
15	Check the cooling system passage for blockage. Is the cooling system passage blocked?	Go to Step 16.	Go to Step 17.
16	1.Remove all the obstructions. 2.Flush the cooling system if necessary. 3.Fill the coolant again. Does the engine still overheat?	Go to Step 17.	The system is normal.
17	Check the coolant fan to see if it does not operate. Doesn't the coolant fan operate?	Go to Step 18.	Go to Step 19.
18	Replace the coolant fan. Refer to Engine Coolant Fan Replacement . Does the engine still overheat?	Go to Step 19.	The system is normal.
19	Check the thermostat to see if it is stuck closed. Is the thermostat stuck closed?	Go to Step 20.	Go to Step 21.
20	Replace the thermostat.	Go to Step 21.	The system is normal.
21	Inspect the water pump for a fault. The impeller blade may have been corroded and broken. Does any water pump fault exist?	Go to Step 22.	The system is normal.
22	Replace the water pump. Does the engine still overheat?	-	The system is normal.