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Alfa Romeo 156 Factory Service Manual (1997-2002)16 · Fault diagnosis
16 · Diagnostics

S05 Engine hissing

Make
Alfa Romeo
Model
156 Factory Service Manual
Year
1997–2002
Section
Noise/vibrations › S05 Engine hissing
Fault diagnosisS05 Engine hissing

S05 Engine hissing

There is buzzing (low frequency noise) coming from the engine, whose intensity varies with the number of revs

StepTest procedureResultAction
1AIR CIRCUIT CHECK

Check:

  • the condition and seal of the air supply circuit
OK

Move onto step 2

Circuit component damaged
  • Replace the component (see Assembly 1048A)

End of diagnosis

2ENGINE EXHAUST CHECK

Check:

  • the condition and the seal of the engine exhaust pipes
OK

Move onto step 3

Pipe, silencer or connector damaged
  • Replace the components (see Assembly 1076B)

End of diagnosis

3VALVE LEAKAGE TEST

Check the condition and the seal of the timing valves

OK

Move onto step 4

Valves damaged
  • Replace the component (see ENGINE OVERHAUL, Subassembly 1016)

End of diagnosis

4CHECK CORRECT OPERATION

Check that the fault is no longer present

OK

End of diagnosis

Fault persists

Incorrect selection of diagnostic procedure

Parts & tools for this job For 1997 Alfa Romeo 156

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