This Preliminary Information communication provides information to the technician about vehicles that may have an engine oil leak that appeared as they were driving the vehicle in extremely cold ambient temperatures. The technician may find the oil leak is coming from the rear main seal. Technician will need to check for proper thermostat operation by following thermostat Diagnosis as outlined in Service Information and replace the thermostat as necessary. Also the technician will remove the cam cover, inspect the positive crankcase ventilation baffle inside, and replace the cam cover if obvious sludge build up is present. Any debris in the positive crankcase ventilation pipes, hoses, the positive crankcase ventilation nipple on the cam cover, and the throttle body should be cleaned out. Technician should inspect the related positive crankcase ventilation hoses/connections for potential damage and replace if necessary. Run the engine at operating temperature for 15 minutes at idle. Then turn the engine off, and drain the engine oil for at least 15 minutes to remove all oil and condensation or water from the crankcase. Follow Service Information repair procedures to repair any oil leaks that were induced as a result of the frozen positive crankcase ventilation system and excessive crankcase pressure. Technician should insure the Engine Control Module calibrations have been installed to adjust the engine oil life monitor to a maximum of 7,500 miles (12,070 KM) as well.
