Motorcraft 3C3Z-6A642-CA Oil Cooler

Engines. Engine Oil Cooler Issues: The two most common failures of this cooler include clogging of the coolant passages and due to deposits, which form as a result of contaminated or unmaintained coolant, and internal leakage between the coolant and oil passages. The first of these issues, clogging of the coolant passages, results in a higher than normal engine oil temperature. 

The best way to prevent damage due to unnoticed engine oil cooler clogging is to have the vehicle maintained by a qualified repair facility that inspects engine oil operating temperatures regularly and is qualified to recognize signs of trouble, as well as performing cooling system flushes approximately every two years, depending on usage.