TM 10-3930-669-20 6.  ENGINE OVERHEATS (ENGINE OIL TEMPERATURE OVER 250°F [121 °C]) (CONT). KNOWN INFO Engine oil level OK. Engine oil temperature is over 250°. Engine oil temperature sensor OK. Engine oil temperature gauge OK. Gauge wire 5 OK. Gauge ground wire OK. Wire 19 faulty. POSSIBLE PROBLEMS Cylinder head fins and air outlet frame dirty. Oil cooler fins dirty. Oil cooler faulty. KNOWN INFO Engine oil level OK. Engine oil temperature is over 250°. Engine oil temperature sensor OK. Engine oil temperature gauge OK. Gauge wire 5 OK. Gauge ground wire OK. Wire 19 faulty. Cylinder head fins and air outlet frame OK. POSSIBLE PROBLEMS Oil cooler fins dirty. Oil cooler faulty. TEST OPTIONS Visual inspection. REASON FOR QUESTION If cylinder head fins and/or air outlet frame are dirty, engine will overheat. TEST OPTIONS Visual inspection. REASON FOR QUESTION If oil cooler fins are dirty, engine will overheat.  If oil cooler fins are clean, oil cooler thermostat is faulty. 2-88