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Symptoms - Engine mechanics A20NFT/LHU

Symptoms - Engine mechanics A20NFT/LHU

Strategy-based diagnosis


1. Perform "diagnostic system check - car" before using symptom tables, if applicable.

2. Review the system function to familiarise yourself with the system's functions. Information is available in Exploded views (A20NFT/LHU), " Description engine components (A20NFT/LHU) and Description lubrication (A20NFT/LHU)


All diagnoses for a car should follow a logical process. Strategy-based diagnosis is a consistent approach for the repair of all systems. The diagnostic flow can always be used to solve a problem arising in the system. You should always use the diagnostic flow in connection with a repair.

Visual/physical inspection


• Check for any retrofitted units that may affect the function of the engine.

• Check easily accessible or visible system components for obvious damage or conditions that may cause this symptom.

• Check that the oil level, oil viscosity and the existing filter are correct.

• Find out exactly under what operating conditions the problem arises. Note factors such as engine speed, ambient temperature, how long it takes to warm up the engine and other specific data.

• If possible, compare the engine noise with a normally functioning engine and convince yourself that you are not trying to fix something that is normal.


Intermittent

Test the car under the same conditions as the customer described in order to confirm that the system is working properly.

Symptom list

Go to a procedure for symptom diagnostics from the following list in order to diagnose the symptom:


• Basic engine misfiring without internal noise in the engine (LDK, LHU)

• Basic engine misfiring in connection with abnormal noise from valve guide (LDK, LHU)

• Basic engine misfiring with abnormal internal noise in lower engine (LDK, LHU)

• Basic engine misfiring with use of coolant (LDK, LHU)

• Engine noise when starting, lasting only a few seconds (LDK, LHU)

• Basic engine misfiring with oil consumption too high (LDK, LHU)

• Noise upper engine, regardless of engine speed (LDK, LHU)

• Noise lower engine, regardless of engine speed (LDK, LHU)

• Noise engine under load (LDK, LHU)

• Engine does not turn over - crankshaft does not rotate (LDK, LHU)

• Coolant in combustion chamber (LDK, LHU)

• Coolant in engine oil (LDK, LHU)

• Whining noise from turbocharger (LDK, LHU)

• Whistling noise from turbocharger (LDK, LHU)

• Oil leakage from turbocharger compressor seal (LDK, LHU)

• Oil leakage from turbocharger turbine seal (LDK, LHU)

• Missing oil supply to turbocharger (LDK, LHU)

• Compression test engine

• Checking/diagnosis of crankcase ventilation system (with turbocharger)

• Diagnosis of drive belt tensioner

• Checking the timing chain

• Leakage test cylinder (A20NFT/LHU)

• Diagnosis of oil consumption (A20NFT/LHU)

• Diagnosis and testing of oil pressure (A20NFT/LHU)

• Diagnosis of oil leakage (A20NFT/LHU)

• Diagnosis of creaking, squeaking and whining drive belt (A20NFT/LHU)

• Drive belt jumping out and increased wear, diagnosis (A20NFT/LHU)