LO 11-8 Outline maintenance procedures and identify tools and methods used to perform maintenance on a diesel engine cooling system

1.5. Verifying the Engine Operating Temperature

Verifying the Engine Operating Temperature
Technicians need to verify whether an engine is reaching operating temperature whenever there is a complaint about an engine overheating or overcooling. Overcooling takes place when the engine does not reach operating temperature. Observations about how long the engine takes to reach operating temperature and the maximum coolant temperature are recorded in these instances. Also inspected for excessive operating temperature are the fault codes associated with the OBD system or the engine protection system logs. The heavy-duty on-board diagnostics (HD-OBD) cooling system monitor also logs codes if the engine does not warm to operating temperature quickly enough to enable other monitors to run. Validate the operating temperature reported by the coolant temperature gauge using an infrared thermometer while investigating excessive operating temperature fault codes. To verify the engine operating temperature, follow the steps in Skill Drill 11-2.