What Causes the Abnormal Noise When Starting the Touareg?
2 Answers
The following are the reasons for the abnormal noise when starting the Touareg: 1. Abnormal noise caused by engine knocking: mainly due to advanced ignition timing, abnormal combustion of fuel auto-ignition, excessive carbon deposits in the combustion chamber, engine overheating, or low-octane gasoline. 2. Abnormal noise caused by piston slap: mainly due to improper piston profile design, excessive cylinder clearance, or incorrect piston assembly. 3. Abnormal noise caused by piston pin issues: mainly due to excessive wear of the piston pin or excessive clearance. 4. Abnormal noise caused by valve issues: mainly due to excessive valve clearance.
I've had a similar experience with my Volkswagen Teramont. There's a rattling noise when starting, most commonly due to worn or misaligned starter motor gears. This sound is usually like a short click because the motor gets stuck or ages when turning, or it could be a loose tensioner in the belt system causing the belt to slip and squeak. Sometimes, it may come from internal engine bearing issues, such as worn crankshaft bearings, which is more serious and produces a dull grinding noise. You should get it checked as soon as possible to avoid the problem escalating into more expensive repairs, like replacing the starter motor, which could cost thousands. A simple method is to start the car and listen for where the sound is coming from. If you're inexperienced, take it directly to a reliable repair shop or dealership for a full diagnosis to save time guessing. Try to avoid rapid acceleration in cold weather during daily starts to reduce the likelihood of the noise occurring.