CRANKSHAFT..............................................................................................................................................................A3

Diagnostics

Problem reported Possible cause Recommended tests or actions Notes

The engine overheats. Defective water pump. Check surface conditions and if necessary replace the pump (with a new gasket).

The engine lacks power and operates erratically.

Faulty thermostat. Replace the thermostat. Scale formation in the water ways in the block and cylinder head. Clean thoroughly. Follow standard instructions for the type of descaler used.

Water pump drive belt slack. Check and adjust belt tension. Insufficient coolant level. Top up the coolant.

Incorrect engine timing. Check timing and carry out accurate timing procedure.

Injection pump out of adjustment (over fueling or defect). Correct pump outlet on test bed to adjust injection output to the stated value.

Air filter blocked. Clean the air filter and replace if necessary.

Incorrect timing of the injector pump. Check the timing and adjust the pump to the correct value.

Defective automatic advance mechanism. Check operation on the injector pump test rig If the values obtained do not accord with the recommended ones, replace the spring in the advance mechanism.

Defective cold start automatic advance device.

Adjust or replace the injector pump. Excessive piston wear. Overhaul the engine and replace worn components.

Incorrect adjustment of the speed regulator. Check and accurately reset the regulator. Contact an approvedBosch agent.

Contact an approvedBosch agent.

Contact an approvedBosch agent.

Diagnostics

Problem reported Possible cause Recommended tests or actions Notes

The engine lacks power and operates erratically.

The engine makes unusual noises.

Partial blockage in nozzles or injector malfunction.

Contamination or water in the feed and injection system.

Incorrect clearance between the cams and the cam followers. Clean the small atomisation nozzles and fully overhaul the injectors.

Carry out an in-depth clean and refill with fuel.

Check clearance and reset accurately.

Faulty turbocharger. Replace the complete unit. Air filter blocked. Clean or replace the air filter.

Defective mixture limiter device. Check that the membrane is not punctured and that the spring is set correctly (check on test rig). Check that there is sufficient air pressure inside the inlet manifold in relation to the engine rpm at full load.

Control linkages between accelerator pedal and regulator lever out of adjustment. Adjust the linkages to ensure that the control lever can reach the maximum flow position.

Defective injector operation. Replace the injectors. Blocked fuel pipes. Remove the pipes, clean and replace any that are very distorted.

Injector pump incorrectly set. Adjust the position of the pump to ensure that injection occurs at the correct advance angle. Contact an approvedBosch agent.

Always bleed the supply system.

Diagnostics

Problem reported Possible cause Recommended tests or actions Notes

The engine makes unusual noises.

The engine emits abnormal amounts of smoke. Black or dark grey smoke.

Crankshaft noise caused by excessive play in one or more main or connecting rod bearings or high levels of end float. Repair the crankshaft bearings and fit under-size bearing shells. Replace the thrust bearings.

Crankshaft out of balance. Check crankshaft alignment.

Flywheel attachment bolts loose. Replace the loose bolts and tighten all bolts to the recommended torque.

Connecting rods misaligned. Replace the connecting rods. Noise from piston gudgeon pins resulting from excessive play in the piston housing or the small end bearing bush. Bushes free to move in small end housing. Replace the gudgeon pin and/or the piston and small end bearing. Replace the bushes.

Noisy valve gear. Adjust clearance between cams and cam followers and check for broken springs; also check for excessive play between the valve stems and guides, cam followers and their housings.

Excessive maximum pump output.

Engine cold start advance mechanism incorrectly set or inoperative.

The injector pump is excessively retarded (or the advance mechanism is defective). Remove the pump and adjust flow rate in accordance with the settings table.

Adjust or replace the injector pump.

Correct the setting, check the mechanism. Contact an approvedBosch agent.

Contact an approvedBosch agent.

Diagnostics

Problem reported Possible cause Recommended tests or actions Notes

The engine emits abnormal amounts of smoke. Black or dark grey smoke.

Smoke is blue, blue-grey, or grey tending towards white.

The injector pump is incorrectly adjusted.

The injector nozzle holes (or some of them) are partially or completely blocked. Correct the adjustment.

Replace the injectors with a new set or clean and recondition the current items using appropriate tools.

Air filter blocked or damaged. Clean the filter element. Replace if necessary

Loss of engine compression due to damaged or worn piston rings, worn or poorly adjusted valves: . Overhaul the engine, or repair/replace only the defective components.

Incorrect injectors, or of mixed types or incorrectly adjusted.

Injector pipes of incorrect internal diameter, ends of pipes crushed resulting from frequent blockages. Replace the injectors.

Check the state of the pipe extremities or connectors, and replace the pipes if necessary.

Injection excessively retarded. Adjust the pump. Contact an approvedBosch agent. Cold start automatic advance mechanism defective. Adjust the injector pump or replace the cold start mechanism.

Defective injectors. Replace the injectors. Oil escaping past the piston rings that may be seized or worn, or because of wear in the cylinder walls. Overhaul the engine.

Engine oil escaping down the inlet valve guides because of wear in the guides or the valve stems. Overhaul the cylinder head.

Engine too cold (faulty thermostat). Replace the thermostat.