Begin the system diagnosis by reviewing the Disassembled Views, Engine Component Description, Lubrication Description, and New Production Information in the 8.1 L Section of the Engine Unit Repair Manual, and the Drive Belt System Description. Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Mechanical in order to identify the correct procedure for diagnosing the system and where the procedure is located.