TM 10-3930-669-20 6.  ENGINE OVERHEATS (ENGINE OIL TEMPERATURE OVER 250°F [121°C]) (CONT). KNOWN INFO TEST OPTIONS Engine oil level OK. Engine oil temperature is over 250° Engine oil temperature sensor OK. Gauge operation test. POSSIBLE PROBLEMS REASON FOR QUESTION Engine oil temperature gauge faulty. Gauge wire 5 faulty. Gauge ground wire faulty. Wire 19 faulty. Cylinder head fins and air outlet frame dirty. Oil cooler fins dirty. Oil cooler faulty. If  engine  oil  temperature  gauge does not read at full scale, gauge is faulty. KNOWN INFO TEST OPTIONS Engine oil level OK. Engine oil temperature is over 250°. Engine oil temperature sensor OK. Engine oil temperature gauge OK. Voltage test. STE/ICE-R #89. POSSIBLE PROBLEMS REASON FOR QUESTION Gauge wire 5 faulty. Gauge ground wire faulty. Wire 19 faulty. Cylinder head fins and air outlet frame dirty. Oil cooler fins dirty. Oil cooler faulty. If  22  to  24  vdc  are  not  present, gauge wire 5 is faulty. ¬ ¬ 2-84