Why Does a New Car Make Abnormal Noises When Starting?

[LaylaRose]

Reasons for abnormal noises when a car starts: 1. The engine temperature is too low: During a cold start, the engine temperature is too low for it to function properly. 2. Thermal expansion of the car's three-way catalytic converter: If there is an abnormal noise when the car is first started, which disappears after a while, it is caused by the thermal expansion of the three-way catalytic converter and is a normal phenomenon. 3. Transmission failure: One of the reasons for abnormal noises when a car starts includes transmission failure, which causes internal gears to rub and produce abnormal noises. 4. Wear of the engine belt or chain: If the engine belt or chain is worn, it can also cause friction or abnormal noises due to idling when the vehicle starts.

[VonAndrew]

I usually enjoy researching cars, and hearing strange noises when starting a new car can be a bit concerning. The most common cause is the engine components breaking in during cold starts—metal parts expanding and contracting for the first time may produce creaking sounds, such as when pistons and cylinder walls are still adjusting to temperature changes. Another possibility is the belt system, especially the drive belt, which may rattle if it's too tight or too loose while the engine is running, particularly noticeable in dry weather. The AC fan often gets blamed too—it automatically activates on startup to dissipate heat, and the unfamiliar humming sound can be mistaken for an issue. In reality, many new cars require a break-in period of 1,000 to 5,000 kilometers, during which the noises naturally fade as components settle. However, if the sound grows louder or is accompanied by vibrations, it's best to check for assembly flaws in components like brake discs or shock absorbers and visit a dealership for a free diagnosis to prevent minor issues from escalating. Overall, most startup noises in new cars are harmless break-in effects that resolve with patience, but abnormal sounds affecting driving safety should not be ignored.

[VanEvelyn]

I experienced the same strange noise when starting my new car. It happened on a winter morning—the car squealed as soon as I turned the key. At first, I thought it was a serious issue. Later, I found out it was just the belt hardening in the cold and slightly rubbing against the flywheel, or the starter gear misaligning, causing a clicking sound during ignition. The AC compressor kicking in might also mix with the blower noise as the new car's system self-tests and adjusts airflow. My advice is not to panic—try driving at different times, like after the engine warms up, to see if the noise persists. If it only happens in cold weather and disappears when warm, it’s likely temperature-related. But if the sound is sharp and rhythmic, like a clunking noise, it could indicate a damaged coolant pump or a loose exhaust pipe—better have a mechanic check it to avoid unnecessary expenses. Normally, such noises decrease as mileage builds up. Just stick to regular maintenance and avoid unnecessary disassembly to preserve the warranty.

[VonJesse]

The strange noise when starting my new car really worries me, especially since it appeared right after purchase. Possible causes vary: first, electrical components like the generator bearing may be old and worn, making a rattling sound during startup; second, poor fuel flow could cause the fuel pump to produce a dull hum due to unstable initial working pressure; third, the chassis may not yet be stable, with screws or suspension squeaking during vibration. Don't overlook environmental factors—for example, a damp garage can corrode parts and amplify noise. Experience tells me that in most cases, it's the car adapting itself—the engine control unit occasionally makes noise while fine-tuning parameters. But if the sound is abrupt or accompanied by a loss of power, such as a roaring noise when accelerating, it might indicate a hidden issue with the turbo or transmission, requiring immediate shutdown and contact with after-sales service. Overall, strange noises in a new car should be carefully observed but not tampered with—patience during the break-in period is key.