What causes the abnormal noise at the moment of starting a 2009 Highlander?
2 Answers
Reasons for abnormal noise at the moment of starting a 2009 Highlander: Engine mount rubber aging or loosening: The engine mount rubber is the rubber block placed between the engine and the vehicle frame. Its function is to reduce the vibration and buffering during engine operation and to secure the engine. Once the engine mount rubber ages or loosens, the engine will shake, and in severe cases, a "clicking" abnormal noise may occur. Excessively rich air-fuel mixture: When the engine's air-fuel mixture is too rich, the symptoms include difficulty accelerating after starting, uneven engine operation; black smoke from the exhaust pipe, accompanied by a clicking noise from the engine, sometimes backfiring; reduced engine power and increased fuel consumption. "Piston slap" abnormal noise: Due to poor lubrication conditions, excessive wear of the piston and cylinder wall leads to the clearance fit tolerance between the piston and cylinder wall exceeding the normal range. When the engine is running, the piston skirt impacts the cylinder wall, producing a crisp "clicking" sound, which is usually more noticeable at idle or low-speed operation.
I also experienced a clicking noise when starting my 2009 Highlander, and later found out it was due to some wear on the starter motor gear, causing slippage and noise during cold starts. After all, this car has some years on it, and many older owners have reported similar issues, especially during cold weather starts. It could also be related to a loose or aged engine belt, as a slack belt can produce squeaking sounds when pulled during startup. I first checked the belt tension and adjusted it if necessary. Additionally, slight shifts in chassis components like suspension ball joints or shock absorbers might cause rattling noises during ignition. My advice is to start with the simple things—listen to where the noise is coming from. If it's minor, have a technician check it during regular maintenance. If it happens frequently, it's best to visit a professional shop to inspect the starter motor or belt system to prevent small issues from turning into bigger problems.
