What Causes the Abnormal Noise During Cold Start That Disappears Afterwards?
4 Answers
Abnormal noise during cold start is caused by components being cold and rigid, insufficient lubrication, improper use of engine oil, etc., which leads to the noise. Additionally, when the drive wheels slip, sudden acceleration should be avoided as it can cause the planetary gears to lock on their shafts. Here are the specific reasons for abnormal noise during cold start: This could be due to improper use of engine oil, excessively low oil pressure, or wear in the hydraulic lifter itself, allowing air to enter the hydraulic lifter, resulting in a "ticking" sound. Wear in the valve rocker arm causes excessive valve clearance, and during cold start, there isn't enough time for the oil film to form and cover it. The sound of the carbon canister solenoid valve operating is normal. A clicking sound within the first half minute that disappears afterward is usually the sound of the three-way catalytic converter expanding as it heats up, which is normal. A loud clicking sound during cold start is mostly an issue with the engine's timing system, such as wear, elongation, or loosening of the timing belt/chain. Solutions for abnormal noise during cold start: To address abnormal noise during cold start, park the car for a day. By then, the engine oil will have mostly flowed back into the oil pan. During a cold start, the oil pump cannot immediately establish oil pressure, and the oil film between components forms gradually. After the engine runs for a while, oil pressure is established, the oil film forms, and the oil temperature rises. Once the engine operates normally, the "ticking" sound disappears.
I've been driving classic cars for years, and there's always a squeaky noise during cold starts that disappears after warming up for three to five minutes. This is mostly an issue with the timing chain or belt system. After a few years of use, the chain stretches and becomes loose when cold, causing friction noise as it wobbles, but tightens up and quiets down when warm. Sometimes, the alternator belt ages and cracks, slipping and hissing during cold starts. Insufficient oil or overly thick viscosity is also common—poor fluidity at low temperatures leads to unlubricated components, but after warming up, the thinner oil flows smoothly and quiets things down. It's recommended to check the oil dipstick monthly; if it's below the minimum line or appears black, change the oil immediately. Also, inspect the belt for cracks and press the tensioner pulley to locate the noise source. Don’t take it lightly—a broken chain can cause engine damage, so get it checked at a repair shop as soon as you notice the issue to prevent minor problems from escalating. Using synthetic oil regularly helps reduce wear.
I remember my old sedan would make a few clicking noises and then stall when starting in winter. I asked my mechanic buddy, and there were quite a few possible reasons. The belt tensioner or water pump bearings could have aged, creating gaps and friction due to thermal contraction and expansion. The cold, thick engine oil, sticky like glue, fails to lubricate properly, causing parts to squeak—once warmed up and thinned, the noise disappears. Lack of oil in the valve lifters is another factor; low oil pressure during cold starts can produce a tapping sound at idle. For a DIY check: pop the hood and listen closely to the source of the noise during a cold start. If it’s near the belt, try spraying some rust inhibitor to see if the noise stops. Regular maintenance is advised, especially checking fluids before seasonal changes. Addressing minor issues early saves money—don’t wait until the belt snaps and leaves you stranded on the road to regret it.
My car had the same issue last time, making a rattling noise for half a minute when cold starting, then stopping. It's usually caused by aged engine oil or chain problems, where the oil flows poorly at low temperatures, leading to hard friction between components. Everything returns to normal after warming up. Worn valve lifters or piston rings could also cause abnormal noises. First, simply check if the engine oil level is sufficient and replace it promptly if deteriorated. Poor maintenance often triggers these problems.
