What to Do About Abnormal Noises During Cold Start?

[DominicDella]

Abnormal noises during cold start may be caused by faulty hydraulic lifters or improper use of engine oil. Below are the specific reasons for abnormal noises during cold start: 1. This could be due to improper use of engine oil, low oil pressure, or wear in the hydraulic lifters themselves, allowing air to enter the hydraulic lifters, resulting in a ticking sound. 2. Wear in the valve rocker arms causing excessive valve clearance, preventing the formation of an oil film in time during cold start. 3. The sound of the carbon canister solenoid valve operating, which is normal. 4. A clicking sound within the first half minute that disappears afterward is usually caused by the expansion of the catalytic converter as it heats up, which is normal. 5. A loud clicking sound during cold start is mostly related to the engine's timing system, such as wear, elongation, or loosening of the timing belt/chain.