MTU 12V4000 G23 Generator Set

Tools: Feeler gauge Y20010128, Torque wrench 60-320 Nm F30047446, Ring socket, 24 mm F30039526

1. Remove cylinder head cover.
2. Install barring tool.
3. Rotate crankshaft with barring tool until marking OT-A1 and pointer are aligned.
4. Check TDC position of piston in cylinder A1 (unloaded rocker arms = firing TDC; loaded = overlap TDC).
5. Check valve clearance with cold engine: inlet valves 0.2 mm, exhaust valves 0.5 mm.
6. Check all valve clearances at two crankshaft positions as per diagram.
7. Use feeler gauge between valve bridge and rocker arm.
8. If deviation exceeds 0.1 mm, adjust valve clearance.
9. Release locknut; insert feeler gauge between valve bridge and rocker arm.
10. Set adjusting screw with Allen key so specified clearance is provided; feeler gauge must just pass through.
11. Tighten locknut to 90 ±9 Nm holding adjusting screw firm.
12. Replace or rectify adjusting screws/locknuts which do not move freely.
13. Check valve clearance.
14. Remove barring tool and install cylinder head cover.

Tools: Rigid endoscope Y20097353

1. Remove cylinder-head cover.
2. Remove injector.
3. Using barring device, turn crankshaft until crankpin of cylinder to be tested has reached BDC.
4. Insert endoscope into cylinder liner through injector seat.
5. Compile endoscopy report using findings table.
6. Depending on findings: take no action, carry out further examination, or contact Service (liner must be replaced).
7. Install injector.
8. Install cylinder-head cover.

1. Loosen clamp.
2. Remove air filter and clamp from flange of intake housing.
3. Verify that there are no objects in the flange of the intake housing and clean it.
4. Place new air filter with clamp onto intake housing.
5. Tighten clamp.
6. Reset signal ring of service indicator.

⚠ Spring/circlip/tensioning roller preload - risk of injury; only use specified tool and equipment.

Tools: Socket adapter or box wrench, Torque wrench

1. Remove guard cover.
2. Slacken screws (1) and (2) by half a turn.
3. Place socket adapter or box wrench on screw (3) and press belt tensioner in arrow direction as far as it will go.
4. Tighten screw (2).
5. Remove the used drive belt.
6. Fit new drive belt.
7. Slacken screw (2) by half a turn (belt tensioner tensions belt).
8. Tighten screw (1) to 42 Nm and screw (2) to 60-65 Nm.
9. Install guard cover.
10. Readjust belt tension after 30 minutes and again after 8 hours engine runtime.

⚠ Hot oil; risk of injury and poisoning; wear protective clothing, gloves and goggles.

⚠ Compressed air risk of injury - do not direct jet at persons.

Tools: Torque wrench 6-50 Nm F30027336

1. Remove clamp.
2. Release Tommy nut and take off cover.
3. Carefully lift rotor, allow oil to drain, remove from housing.
4. Release rotor cover nut and take off rotor cover.
5. Remove filter sleeve.
6. Measure thickness of oil residues; if exceeds 45 mm, shorten maintenance interval.
7. Disassemble rotor tube, conical disk and rotor base; wash with cleaner and blow out with compressed air.
8. Check sealing rings, fit new ones if necessary.
9. Insert new filter sleeve with smooth paper surface facing the wall.
10. Mount rotor cover with sealing ring; tighten rotor cover nut 35-45 Nm.
11. Place rotor in housing and check for ease of movement.
12. Fit sealing ring on housing, fit cover, tighten Tommy nut by hand.
13. Fit clamp and tighten 8-10 Nm.
14. Tighten cover nut to 5-7 Nm.

⚠ Hot oil; avoid contact with skin, do not inhale oil vapor; wear protective clothing, gloves and goggles/safety mask.

Tools: Torque wrench 6-50 Nm F30027336

1. Remove cover with O-ring.
2. Remove filter element from housing.
3. Insert new filter element in housing.
4. Fit cover with new O-ring.
5. Tighten screws of cover to specified torque 10 Nm ±2 Nm.
6. Replace further oil separator elements the same way.
7. Checking diaphragm: remove cover, take off spring, seal and diaphragm.
8. Check diaphragm for damage, fit new if damaged.
9. Mount diaphragm on housing.
10. Install new seal and spring with cover.
11. Tighten cover screws to 10 Nm ±2 Nm.

⚠ Before barring the engine, ensure that nobody is in the danger zone.

Tools: Barring tool F6555766, Ratchet F30006212

1. Remove guard plate.
2. Engage barring tool with ring gear and mount on flywheel housing.
3. Set ratchet onto barring tool.
4. Rotate crankshaft in engine direction of rotation; apart from normal compression resistance there should be no abnormal resistance.
5. For barring-tool removal follow reverse sequence.

⚠ Before barring or starting the engine, ensure that nobody is in the danger zone.

⚠ Check that all protective devices have been reinstalled and all tools removed.

1. Release latch of connector X4 and disconnect connector from engine governor.
2. Bar engine in unloaded condition: press START button.
3. Let crankshaft rotate until oil pressure is indicated.
4. Engine start is automatically interrupted when specified starting period expires; re-start after approx. 20 seconds.
5. Connect connector X4 to engine governor and latch in position.

⚠ Coolant is hot and under pressure - risk of injury and scalding; let engine cool down; wear protective clothing, gloves and goggles.

⚠ Cold coolant in hot engine can cause thermal stress - fill only into cold engine.

Tools: Suitable pump with hose

1. Turn breather valve of coolant expansion tank counterclockwise to first stop and allow pressure to escape.
2. Continue to turn counterclockwise and remove.
3. Connect suitable pump with hose to drain valve of engine coolant pump.
4. Undo vent line union at distributor piece.
5. Open drain valve and pump coolant into engine at 0.5 bar minimum.
6. Tighten union if coolant leaks out.
7. Fill expansion tank until overflow edge is reached; close drain valve.
8. Fit breather valve and close.
9. Start engine; after running without load for 10 seconds, stop engine.
10. Remove breather valve; check coolant level and top up as necessary.
11. Repeat start/stop steps until coolant no longer needs topping up.
12. Disconnect pump and hose; run engine unloaded some minutes and recheck level.

⚠ Hot oil; risk of injury and poisoning; wear protective clothing, gloves and goggles; avoid contact with skin; do not inhale oil vapor.

Tools: Torque wrench F30027337, Ratchet adapter F30027341

1. Provide suitable container to collect the oil.
2. Remove drain plug(s) and drain oil.
3. Install drain plug(s) with new sealing ring.
4. Drain residual oil at equipment carrier drain plugs (approx. 7 L, 12 L, 5 L).
5. Replace engine oil filter.
6. Tighten drain plugs (2) and (3) to 100 ±10 Nm.
7. Open cover of filler neck and pour oil in up to 'max.' mark.
8. Close cover of filler neck.
9. Check engine oil level.
10. After oil change and filter replacement, turn engine on starting system.

⚠ Hot oil; avoid contact with skin; do not inhale oil vapor.

Tools: Filter wrench F30379104

1. Remove oil filter using the filter wrench.
2. Clean the sealing surface of the filter head.
3. Check condition of new sealing ring and coat it with oil.
4. Screw on and tighten new oil filter by hand.
5. Replace further oil filters the same way.
6. After each oil change and filter replacement, bar engine with starting system.
7. Check oil level.

⚠ Fuels are combustible - risk of fire and explosion; avoid naked flames, sparks, ignition sources; do not smoke.

Tools: Filter wrench F30379104

1. Remove easy-change filter using filter wrench.
2. Clean sealing face of filter head.
3. Slightly lubricate seal on easy-change filter.
4. Screw on filter by hand until seal makes contact and tighten finger-tight.
5. Replace other easy-change filters the same way.
6. Vent the fuel system.