159364-4300 ZEXEL 9 421 613 402 BOSCH UNION NUT 9421613402 1593644300 1157792720

You must read and understand the warnings and instructions contained in the Safety section of this manual before performing any operation or maintenance procedures.Walk-Around Inspection
Inspect Engine for Leaks and Loose Connections
For maximum service life of your truck engine, make a thorough under the hood inspection before starting the engine. Look for such items as oil or coolant leaks, loose bolts, worn fan belts, loose connections and trash build-up. Remove trash build-up and have repairs made as needed.Check the fluid levels more frequently than the recommended maintenance intervals and continue to monitor fluid levels until any leak is found and fixed.* Wipe all fittings, caps and plugs before performing maintenance to reduce the chance of system contamination. Inspect:* Radiator and ATAAC core for leaks and trash build-up.* Radiator and ATAAC air intake system hoses and elbows for cracks and loose clamps.* Fan and accessory drive belts for cracks, breaks or other damage.Belts for multiple groove pulleys must be replaced as matched sets. If only one belt of a two or three belt set is replaced, it will carry more of a load than the belts not replaced since the older belts are stretched. The additional load on the new belt could cause it to break. Inspect:* Water pump for coolant leaks. The water pump seal is lubricated by coolant in the cooling system. It is normal for a small amount of leakage to occur as the engine cools down and parts contract. If leaks are found, check the coolant level frequently and continue to monitor the level until the water pump is repaired. Excessive coolant leakage may indicate the need to replace the water pump seal.For removal and installation of water pumps and/or seals, see the Service Manual for this engine or consult your Caterpillar dealer. Inspect:* Lube system for leaks, such as front and rear crankshaft seals, oil pan, oil filters and valve covers.* Fuel system for leaks, loose fuel line clamps and fittings and loose or worn hoses.
Fuel line clamps should not be over torqued. Over torqueing causes the clamps to butterfly, which results in low clamping force and fuel line vibration and eventual failure.
Tighten fuel line clamps as required using 6V4980 Torque Screwdriver Tool Group. The standard torque for these fasteners (#10 screw) is 20 lb inch (2.26 N m).* Inspect wiring and wiring harnesses for loose connections and worn or frayed wires. Inspect:* Air intake system hoses and elbows for cracks and loose clamps. * ECM to cylinder head ground strap and starter negative cable for good connection and condition.All guards must be in place. Repair or replace missing or damaged guards.Check condition of batteries and the level of electrolyte, unless equipped with a maintenance free battery.Refer to OEM truck owner manual or manufacturers' recommendations for battery maintenance.