Vortec 1600 - Engine Fails to Reach Normal Operating Temp

2-6 Engine Cooling Industrial 1.6L
Thermostat Diagnosis (Cont’d)
Use the following procedure in order to check for a cold engine, slow warm–up or the engine does not reach normal
operating temperature of 86.6°C (188°F) to 96.6°C (206°F):
1. Relieve the pressure and carefully remove the radiator cap.
2. Rub a 86.6°C (188°F) temperature stick on the thermostat housing.
3. Warm up the engine at a fast idle. Watch for coolant flow before the mark begins to melt.
• If the coolant flows, before the mark begins to melt, install a new thermostat. Recheck the system in order to
ensure the system is operating properly.
• If there is coolant flow after the mark begins to melt, the problem is caused by something other than a faulty
thermostat.
A temperature stick is a pencil like device that has a wax material containing certain chemicals. These chemicals melt
at a certain temperature. Use a temperature stick in order to determine a thermostat’s operating temperature by
rubbing the 86.6°C (188°F) and the 96.6°C (206°F) sticks on the thermostat housing. The marks made by the sticks
should melt when the coolant temperatures of 86.6°C (188°F) to 96.6°C (206°F) are reached. These temperatures are
the normal operating range of the thermostat. If the coolant flows as indicated in the preceding procedures, the
thermostat is considered to be operating properly.
Engine Fails to Reach Normal Operating Temperature
Step Action Value(s) Yes No
DEFINITION: The engine fails to reach the normal operating temperature of 86.6
°
C (188
°
F) to 96.6
°
C (206
°
F).
1
Check the thermostat.
Is the thermostat stuck open or was the wrong type of
thermostat previously installed?
—
Go to Step 2
—
2
Replace the thermostat.
Is the problem corrected?
—
System OK
—