The thermostat may fail to close completely, causing the Check Engine Light to illuminate. This problem will prevent the engine from reaching normal operating temperature; a new thermostat should be installed.
Average mileage: 88,000 (78,000–98,000)
Engines affected: 5.9L 6 Cylinder Diesel Turbo, 6.7L 6 Cylinder Diesel Turbo
11 people reported this problem