Engine Fails To Reach Normal Operating Temperature

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. 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?	System OK	Go to Step 6
6	Install the correct replacement thermostat. Refer to Engine Coolant Thermostat Housing Replacement (LY2, LH6, LY5, LMG, LY6) . Is the repair complete?	Go to Step 7	-
7	Run the engine in order to verify the repair. Does the engine fail to reach normal operating temperature?	-	System OK