John Deere 4045D150 / 4045T150 / 4045T250 / 6068T250 Engine

⚠ Engine valve clearance must be checked and adjusted when the engine is cold.

⚠ Always disconnect the NEGATIVE (-) battery terminal before adjusting valves.

Tools: JD281A, JDG820 or JDE83 Flywheel Turning Tool, JDE81-4 Timing Pin, Feeler gauge, Torque wrench

1. Disconnect the NEGATIVE (-) battery terminal to prevent accidental starting.
2. Remove the rocker arm cover and crankcase ventilator tube.
3. Remove the plastic plugs or cover plate from the flywheel housing timing holes.
4. Rotate the engine clockwise with a flywheel turning tool to No. 1 cylinder TDC compression stroke and insert the timing pin.
5. Check and adjust intake valve clearance to 0.35 mm (0.014 in) and exhaust valve clearance to 0.45 mm (0.018 in).
6. Loosen the locknut on the rocker arm adjusting screw; turn the screw until a feeler gauge slips with a slight drag.
7. Hold the adjusting screw and tighten the locknut to 27 Nm (20 lb-ft); recheck clearance.
8. Replace the rocker arm cover and crankcase ventilator tube.

Tools: Open-end wrench, Torque wrench

1. Slightly loosen the fuel return line connector at the fuel injection pump.
2. Operate the fuel supply pump primer lever until fuel without air bubbles flows from the fuel return line connection.
3. Tighten the return line connector to 16 Nm (12 lb-ft).
4. Leave the hand primer in the inward position toward the cylinder block.

⚠ Escaping diesel fuel under pressure can penetrate the skin, causing serious personal injury. Use a piece of cardboard or wood, not your hands, to search for leaks.

1. Loosen the air bleed vent screw two full turns by hand on the fuel filter base.
2. Operate the supply pump primer lever until fuel flow is free of air bubbles.
3. Tighten the bleed plug securely and continue operating the hand primer until pumping action is not felt.
4. Push the hand primer inward (toward the engine) as far as it will go.
5. Start the engine and check for leaks.

1. Change oil when the engine is warm.
2. Remove the plug from the outlet in the base frame and screw in an owner-supplied drain hose.
3. Open the valve at the oil pan outlet and drain oil into a suitable container.
4. Close the valve, remove the drain hose and replace the plug.
5. Refill the engine with the recommended oil and dispose of waste oil in an approved manner.

⚠ Overtightening can damage the filter housing.

Tools: Filter wrench

1. Use a filter wrench to remove the old filter and dispose of it in an approved manner.
2. Make sure the gasket from the old filter is removed and discarded.
3. Lubricate the rubber gasket on the new filter and screw it on until the gasket meets the sealing surface.
4. Using hands only, tighten the filter three-quarters to one and one-quarter turn farther.
5. Fill the engine with recommended oil, start the engine and check for leakage, then stop and recheck the oil level.

Tools: Dial indicator, JD281A, JDG820 or JDE83 Flywheel Turning Tool

1. Run the engine to operating temperature and stop; remove the belts.
2. Grasp the vibration damper with both hands and attempt to turn it in both directions; if rotation is felt, the damper is defective and should be replaced.
3. Position a dial indicator so the probe contacts the damper outer diameter.
4. With the engine at operating temperature, rotate the crankshaft using a flywheel turning tool and note the indicator reading.
5. Replace the damper if runout exceeds 1.50 mm (0.060 in).

1. Remove and clean the crankcase vent tube every 12 months or 600 hours (shorter intervals in dusty conditions).
2. Install the vent tube; be sure the O-ring fits correctly in the rocker arm cover for the elbow adapter.
3. Tighten the hose clamp securely.

⚠ Allow the engine to cool before working on the cooling system. Open the filler cap carefully using protective clothing when the engine is warm.

1. Pressure test the entire cooling system and pressure cap if not previously done.
2. Slowly open the filler cap to relieve pressure.
3. Open the engine block drain valve on the left side of the engine and drain all coolant.
4. Open the radiator drain valve and drain all coolant from the radiator.
5. Remove the thermostats, install the cover and tighten cap screws to 47 Nm (35 lb-ft).
6. Close all drain valves, fill with clean water, run the engine about ten minutes, then stop and drain before rust and sediment settle.
7. Fill with clean water and a cooling system cleaner such as Fleetguard RESTORE and RESTORE PLUS; follow label directions.
8. Drain cleaner, flush with water, run the engine ten minutes and drain.
9. Close all drain valves and install thermostats using a new gasket.
10. Add coolant to the radiator until it touches the bottom of the filler neck.
11. Run the engine to operating temperature and check the coolant level and system for leaks.

⚠ Explosive releases of fluids from pressurized cooling systems can cause serious burns. Shut off engine and only remove filler cap when cool enough to touch with bare hands.

Tools: D05104ST Tester

1. Remove the radiator cap and attach it to the D05104ST Tester.
2. Pressurize the cap to 70 kPa (0.7 bar)(10 psi); the gauge should hold pressure for 10 seconds.
3. If the gauge does not hold pressure, replace the radiator cap; retest the cap turned 180°.
4. Allow the engine to cool and carefully remove the radiator cap.
5. Fill the radiator with coolant to the normal operating level.
6. Connect the gauge and adapter to the radiator filler neck and pressurize the cooling system to 70 kPa (0.7 bar)(10 psi).
7. With pressure applied, check all cooling system hose connections, radiator and engine for leaks.

⚠ Escaping diesel fuel under pressure can penetrate the skin. DO NOT overtighten the retaining ring.

Tools: Compressed air

1. Close the fuel shut-off valve, if equipped, and thoroughly clean the fuel filter assembly and surrounding area.
2. Loosen the drain plug and drain fuel into a suitable container.
3. Firmly grasp the retaining ring and rotate it counterclockwise one-quarter turn; remove the ring with filter element.
4. Inspect the filter mounting base for cleanliness and clean as required.
5. Install the new filter element onto the mounting base, properly indexed and firmly seated.
6. If equipped with a water separator, remove the element from the bowl, drain and clean the bowl, dry with compressed air, and install onto the new element.
7. Install the retaining ring making certain the dust seal is in place; hand-tighten about one-third turn until it snaps into the detent.
8. Open the fuel shut-off valve and bleed the fuel system; tighten the bleed plug.

1. The first 100 hours on a new or reconditioned engine are critical to its life and performance.
2. Constantly check the engine temperature and oil pressure gauges.
3. Oil consumption is greater during break-in as piston rings and cylinder liners take time to seat.
4. Change engine oil and filter at 100 hours, and again at 250 hours.
5. Retighten head bolts and adjust valves at 50 hours.
6. Maintain at least a 75% load for the first 100 hours; never below 50%.

1. Unload the generator.
2. Run the engine for a 3 to 5 minute cool down period.
3. Move the engine control switch to the STOP position until the engine stops completely.
4. Put the battery switch in the OFF position.
5. Shut off the fuel valve at the tank.