LOCATOR 9U6171 - Caterpillar

All 3406, 3408 And 3412 D.I. EnginesReference: Service Magazine, February 15, 1982, Page 6. The article "New Fuel Nozzle Adapter Assembly Used," tells about the release of new fuel nozzle adapters. These new fuel valve adapters were released because of problems with cracks in the former adapters.When troubleshooting the above engines, remember that fuel in the cooling system or coolant in the engine oil are two common indications of a fuel nozzle adapter failure.
It may save troubleshooting time on these engines, if the fuel nozzle adapters are checked for cracks first. If the adapters have cracks, they will normally be in the area of the threads.
Some other possible indications of an adapter failure are fuel in (dilution of) the oil, coolant leakage into the cylinders, and a large amount of bubbles in the radiator.