What Causes Noise After Cold Start of a Car?
3 Answers
Reasons for noise after cold start of a car: 1. Oil viscosity: When the engine is cold, the oil viscosity is higher. If the selected oil is too thick, it will cause additional wear on the starter motor and battery. However, if the oil is too thin, it may not form a sufficient protective film under high-temperature conditions, leading to insufficient lubrication and increased wear on components, resulting in noise. 2. Engine carbon deposits: Over time, old oil becomes thinner, leading to an accumulation of carbon deposits. 3. Engine resonance: Slippage due to aging of the water pump belt or engine belt can cause abnormal noise, or lack of lubrication in components such as the water pump impeller, water pump bearings, or generator bearings may lead to wear and noise.
There's noise after a cold start, which reminds me of my over ten years of driving experience. I've encountered this issue several times, and there are quite a few reasons. For example, when the engine just starts, the oil hasn't fully lubricated, causing internal parts to rub and make noise; or the belts are old or loose, producing squeaky sounds during operation. Additionally, in cold weather, metal contracts, leading to abnormal noises from the exhaust pipe or other connecting parts. If not addressed promptly, minor issues can escalate, affecting the engine's lifespan. I usually start by identifying the sound characteristics: if it's a brief buzzing noise, it might be more related to the oil pump; if it's continuous, the belts or chains need checking. It's best to visit a reputable repair shop early. After replacing old or worn parts, the car becomes much quieter and more reliable to drive. Regular maintenance checks on fluid quality can prevent many noise issues.
When I first bought the car, I was really afraid of this issue—there was a rattling noise during startup, which felt uncomfortable and unsettling. I did some research and learned that such noises often come from severely worn belts, like the alternator belt, which can make a creaking sound during cold starts if it's loose or cracked. It could also be due to overly thick oil in the oil pan not flowing promptly to engine parts, causing friction sounds. Additionally, temperature fluctuations can make plastic components expand and contract, leading to odd noises. I suggest newbies like me not panic right away—just do a simple check on belt tension and oil levels. If that doesn’t help, head to a repair shop where mechanics can use tools to pinpoint the real cause. Although minor noises are common, ignoring them can accelerate part wear. After I replaced the alternator belt once, the noise disappeared, and the car ran smoother. Don’t delay repairs too long—safety first.
