My 2018 Silverado with the 5.3 liter has only 22,000 miles on it. Ever since it had about 10,000, it has been making a temporary clicking noise on warm/hot starts. It is faint but noticeable with the radio off, sounds like: click click....click click.....click click....click. Lol
I haven’t noticed any other issues with the engine besides that. I do notice 1-2 very small metal specs when I check the oil usually, but my 2015 Silverado has the same thing. I got it checked out at the dealership and they said it was the fuel injectors, obviously I’m skeptical of that diagnosis. Could it be an issue with the active fuel management lifters smacking the cam?