Engine Fails To Reach Normal Operating Temperature

WARNING: This page is about a different car, the 2005 GMC Sierra and 2005 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
1	Did you review the Symptoms-Engine Cooling diagnostic information and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Engine Cooling
2	Verify that the engine does not reach normal operating temperature. Does the engine reach normal operating temperature?	System OK	Go to Step 3
3	Inspect the coolant level. Is the coolant level below the add mark?	Go to Step 4	Go to Step 5
4	Add coolant as necessary. Perform a cooling system pressure test. Does the cooling system hold pressure?	System OK	Go to Step 5
5	Inspect for a stuck open, missing, or incorrect thermostat. Refer to Thermostat Diagnosis . Is the thermostat operating properly?	Go to Step 6	Go to Step 8
6	Is the vehicle equipped with a 6.6 L diesel engine?	Go to Step 7	Go to Step 8
7	Inspect for a faulty turbocharger coolant bypass valve Is the turbocharger coolant bypass valve functioning properly?	-	Go to Step 9
8	Install the correct replacement thermostat. Refer to Thermostat Replacement (4.3L Engine) or Thermostat Replacement (6.6L (LLY) Engine) or Thermostat Replacement (8.1L Engine) . Is the repair complete?	Go to Step 10	-
9	Install a new turbocharger coolant bypass valve. Refer to Turbocharger Coolant Bypass Valve Replacement (6.6L (LLY) Engine) . Is the repair complete?	Go to Step 10	-
10	Run the engine in order to verify the repair. Does the engine fail to reach normal operating temperature?	-	System OK