TEST RESULTS

Connect the diagnostic equipment to the diagnostic socket and check that there are no faults in the engine management control unit.

Move on to Step 2

Error detected in the engine management control unit.

Continue following the instructions on the diagnostic equipment

Disconnect the services belt and check whether the noise disappears

Move on to Step 3

The noise disappears

Proceed as instructed in

 See table S010 ENGINE WHILSTLING / SERVICES BELT NOISY

Carry out a test to locate the exact area where the knocking is coming from using suitable equipment.

Move on to Step 4

1. The knocking is coming from the cylinder head

2. The knocking is coming from the crankcase.

1. Move on to Step 5

2. Move on to Step 4

Carry out a test to identify the circumstances in which the crankcase knock occurs.

Move on to Step 5

1. The knocking occurs with the engine cold and decreases when warm; when accelerating it is audible on overrun.

2. The knocking occurs with the engine cold and increases when the accelerator pedal is pressed to the floor and the gear ratio is long

3. The knocking is heard at all temperatures

4. The knocking is heard at all temperatures and decreases when the clutch pedal is pressed.

1. Overhaul the engine: in particular, check the condition of the pistons and, if necessary, replace them

 Op. 1028H10 CONNECTING ROD AND PISTON SET - R.R

2. Overhaul the engine: in particular, check the condition of the main bearings and, if necessary, replace them

 Op. 1004E20 ENGINE - DISMANTLING AND REASSEMBLY FOLLOWING OP.1004E10 - WASH AND CHECK DISMANTLED COMPONENTS - REFITTING CYLINDER HEAD AND OIL SUMP - DOES NOT INCLUDE OPERATIONS ON CYLINDER HEAD AND AUXILIARY UNITS

3. Overhaul the engine: in particular, check the condition of the connecting rod bearings and, if necessary, replace them

 Op. 1004E20 ENGINE - DISMANTLING AND REASSEMBLY FOLLOWING OP.1004E10 - WASH AND CHECK DISMANTLED COMPONENTS - REFITTING CYLINDER HEAD AND OIL SUMP - DOES NOT INCLUDE OPERATIONS ON CYLINDER HEAD AND AUXILIARY UNITS

4. Overhaul the engine: in particular, check the crankshaft

If the vehicle is not often used, it is possible that an accentuated knocking of the tappets will be heard for a few minutes during start up, which will then gradually decrease.

Move on to Step 6

Tappet knocking persists.

Check operation of hydraulic tappets

and replace those that do not work.

Overhaul the cylinder head and, in particular, check:

- no cam wear;

- cam axis clearance;

- valves and springs.

End of diagnosis

Cam wear or incorrect camshaft clearance

Repair or replace the components concerned.