Why is the Kia Ceed's engine making a knocking noise?

Recently, my Kia Ceed has been making a loud knocking noise when I start the engine. It seems to go away after a few minutes, but it's still concerning. What could be causing this and how can I fix it?

It's possible that there could be an issue with the engine's hydraulic lifters. This is a common problem with Kia Ceed's and can be fixed by taking it to a mechanic for a valve adjustment.

Another possible cause could be worn or damaged engine bearings. This could be due to low oil levels or using the wrong type of oil. Make sure to check your oil levels regularly and use the recommended oil for your vehicle.

If the knocking noise is only happening when the engine is cold, it could be a sign of piston slap. This is when the pistons are slightly loose and make noise when the engine is cold. It's not a major issue, but if it bothers you, you can have it checked and possibly repaired.