3022719 - S01 ENGINE KNOCK
The engine makes a cyclical noise, the intensity of which varies with the load and is noticeable during brisk acceleration and when long gear ratios are used| Results of the tests | ||||||
| 1 | CHECKING WITH DIAGNOSTIC EQUIPMENT | All OK | Problems met | Operation | ||
|---|---|---|---|---|---|---|
Connect the diagnostic equipment to the diagnostic socket and check:
| Continue to Step 2 | An error is detected in the control unit | Continue following the instructions for the diagnostic equipment | |||
| 2 | CHECKING AUXILIARY COMPONENTS CHECK | All OK | Problems met | Operation | ||
Disconnect
the service belt and check whether the noise disappears.
| Continue to Step 3 | The noise disappears | See table S10 ENGINE WHILSTLING / SERVICES BELT NOISY' | |||
| 3 | CHECKING SITE OF KNOCKING | All OK | Problems met | Operation | ||
| Carry out a test to locate the precise area from which the knocking is coming, using suitable equipment | Continue to Step 4 | The knocking is coming from the cylinder head | Continue to Step 5 | |||
| The knocking is coming from the cylinder block/crankcase | Continue to Step 4 | |||||
| 4 | CHECKING CRANKCASE KNOCK | All OK | Problems met | Operation | ||
| Carry out a test to identify the conditions in which the knocking from the crankcase occurs. | Continue to Step 5 | The knocking occurs with the engine cold, decreases with the engine hot and can be heard when releasing the accelerator. | Overhaul the engine, in particular check the condition of the pistons and replace them if necessary. Op. 1028H10 | |||
| The knocking occurs with the engine cold and increases during full acceleration with a long ratio. | Overhaul the engine: in particular, check the condition of the main bearings and replace them if necessary. Op. 1024A10 | |||||
| The knocking is of a low intensity when cold but increases with the engine warm | Overhaul the engine: in particular, check the condition of the gudgeon pins and replace them. Op. 1028H60 | |||||
| The knocking can be heard at all temperatures | Overhaul the engine: in particular, check the condition of the big end bearings and replace them if necessary Op. 1024A10 | |||||
| The knocking can be heard at all temperatures and decreases when the clutch pedal is pushed. | Overhaul the engine and check the crankshaft end float. | |||||
| 5 | CHECKING TAPPET KNOCK | All OK | Problems met | Operation | ||
| If the car is not used frequently, an accentuated knocking sound may be heard from the tappets for a few minutes upon start up before gradually disappearing (see specific S.N.) | Continue to Step 6 | Tappet knock persists | Continue to Step 6 | |||
| 6 | CHECKING CYLINDER HEAD | All OK | Problems met | Operation | ||
Overhaul the cylinder head and, in particular, check
| Continue to Step 7 | Cam worn or incorrect camshaft clearances | Restore or replace the components involved | |||
| Tappets noisy | Check hydraulic tappet operation (as per standard procedure) and replace any that are not working | |||||
| 7 | CHECKING CORRECT OPERATION | All OK | Problems met | Operation | ||
| Check that the fault is no longer present | Fault persists | Search for the fault starting from another symptom' | ||||
