What Causes Abnormal Car Starting Sounds?
2 Answers
Abnormal sounds during car startup may result from the following reasons: 1. Hydraulic lifters: Air entering the hydraulic lifters due to low oil pressure or wear in the lifter itself. 2. Valve clearance: Excessive valve clearance caused by wear in the valve rocker arm. 3. Dirty throttle body: Accumulation of sludge and carbon deposits leading to a dirty throttle body. 4. Carbon canister purge valve operation sound: This is a normal sound and the vehicle can continue to be used. If the sound is too loud, it's recommended to have it checked at a 4S shop. 5. Catalytic converter: A "clicking" sound within half a minute after a cold start, which usually disappears afterward. This is typically caused by the expansion of the catalytic converter when heated.
I've been driving for over twenty years, and the most annoying thing is strange noises during startup. That rattling sound is usually caused by a weak or aging battery, leading to unstable voltage that prevents the starter motor from turning properly. It gets worse in cold winter temperatures, and worn starter motor gears can also produce a clattering noise, which is nerve-wracking. When I was younger, I taught myself car repairs—first, I'd pop the hood to check for battery terminal corrosion and clean any green rust with sandpaper. Then, I'd listen to pinpoint the source of the noise. If simple fixes didn’t work, I’d head straight to the auto shop. Delaying repairs can damage the engine’s core components, adding hundreds to repair costs, not to mention the risk of stalling mid-drive. Regular maintenance of the battery and electrical system is crucial—it extends part lifespan and saves both hassle and money.
