Detonation knocks
Comment. Detonation knock - a sharp double-tone knock that appears with a dynamic increase in engine load (the engine control system malfunction indicator lamp may light up).
1. The octane number of gasoline is lower than required (if knocks appeared immediately after refueling the car with fuel). 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 data of the coolant temperature gauge on the instrument panel (see «Checking the technical condition of the cooling system») and, if the engine does overheat, correct the cause of the engine overheating.
3. Faulty knock sensor. Run diagnostics on the engine management system (see «Engine management system»). Check knock sensor, replace defective (see «Knock sensor - check and replace»).
4. Faulty engine management system. Run diagnostics on the engine management system (see «Engine management system»). Replace defective parts.
5. Carbon deposits on valves and combustion chambers (frequent short trips). Self-cleaning requires a long motorway trip 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 detonation knocks, see above)
1. Chirping knock in the upper part of the engine: gaps in the valve drive are violated. Check the technical condition of the engine (see «Engine - condition check»).
2. Wear of pistons, cylinders, malfunction of the timing mechanism. Check the technical condition of the engine (see «Engine - condition check»). Repair engine.
The starter makes a lot of noise (grinding)
1. Loose starter mounting bolts. Check starter screw tightening torque (see «Starter - removal and installation») and tighten them if necessary.
2. The starter or its solenoid relay is faulty. Check starter (see «Starter»). Replace defective solenoid or replace starter assembly (see «Starter - removal and installation», cm. «Starter - repair»).
Increased exhaust noise
1. The tightness of the exhaust system is broken. Determine the location of the leak (see «Check of a technical condition of system of release of the fulfilled gases»). Check the tightening torques of the threaded connections of the fasteners. If it is not possible to restore the tightness of the system in this way, replace the seal.
2. The tightness of the parts of the exhaust system due to corrosion or mechanical damage (see «Check of a technical condition of system of release of the fulfilled gases»). Check the technical condition of the exhaust system and replace defective parts.