What causes the Kia K5 to make a rattling noise when cold but not when warm?

[SaraLee]

The reason why the Kia K5 makes a rattling noise when cold but not when warm is: 1. During a cold engine start, the oil pump cannot immediately establish oil pressure, and oil films cannot form between components, leading to insufficient lubrication during cold starts. Whether it's hydraulic lifters or mechanical rocker arms, there will be some valve clearance, resulting in the rattling noise; 2. After the engine runs for a while, oil pressure is established, oil films form, and the engine oil temperature rises. Once the engine operates normally, the rattling noise disappears. The Kia K5 is a mid-size sedan under Dongfeng Yueda Kia. Taking the 2020 Kia K5 as an example, its body dimensions are 4980mm in length, 1860mm in width, and 1445mm in height, with a wheelbase of 2900mm. The body structure is a 4-door, 5-seater sedan. In terms of power, the 2020 Kia K5 is equipped with 1.5T and 2.0T turbocharged engines, paired with a 7-speed dual-clutch transmission and an 8-speed automatic transmission.