Detonation knocks
Note: Detonation knock is a sharp double-tone knock that appears when the engine load increases dynamically (the engine management system malfunction indicator light may come on).
1. The octane number of gasoline is lower than required (if the knocking sounds appeared immediately after refueling the car). Drain the gasoline from the tank and fill the car with high-quality fuel. You can try to increase the octane number of gasoline with a special additive.
2. Engine overheating. Check the coolant temperature gauge on the instrument cluster (see "Checking the technical condition of the cooling system") and if the engine is indeed overheating, eliminate the cause of the engine overheating.
3. The knock sensor is faulty. Perform diagnostics of the engine management system (see "Engine management system"). Check the knock sensor, replace the faulty one (see "Knock Sensor - Checking and Replacing").
4. The engine management system is faulty. Perform diagnostics of the engine management system (see "Engine management system"). Replace faulty parts.
5. Carbon deposits on valves and combustion chambers (frequent short distance travel). Self-cleaning requires a long drive on the highway at a speed of at least 90 km/h. If this is not possible, special fuel additives can be used to remove carbon deposits.
Noises and knocks in the engine (except for detonation knocks, see above)
1. A whirring knocking noise from the top of the engine: the valve drive clearances are incorrect. Check the technical condition of the engine (see "Engine - technical condition check").
2. Wear of pistons, cylinders, malfunction of the gas distribution mechanism. Check the technical condition of the engine (see "Engine - technical condition check"). Repair the engine.
The starter operates with a loud noise (grinding)
1. The starter mounting bolts are loose. Check the tightening torque of the starter threaded connections (see "Starter - removal and installation") and tighten them if necessary.
2. The starter or its solenoid relay is faulty. Check the starter (see "Starter"). Replace the faulty solenoid relay or replace the starter assembly (see "Starters - removal and installation", cm. "Starter - repair").
Increased exhaust noise
1. The exhaust system is not sealed. Determine the location of the leak (see "Checking the technical condition of the exhaust system"). Check the tightening torques of the threaded connections of the fasteners. If this method fails to restore the tightness of the system, replace the seal.
2. The tightness of the exhaust system parts is broken due to corrosion or mechanical damage (see "Checking the technical condition of the exhaust system"). Check the technical condition of the exhaust system and replace faulty parts.