After sitting for a few hours, 2016 Yukon 5.3, 24,000 miles, has a 1/2 second lifter rattle noise. (As it sounds like it to me). I am considering buying this certified car from a
GMC dealer. Could this noise be normal? And if not lifters, what the hell could it be?

 

Is it a quick buzz/rattle right after startup, very quick as the engine is revving then goes away immediately before it idles down? My 2017 Burb does that, and I noticed it even more on a 2018 Sierra loaner that I had. Both of those have the 5.3. It’s not a tick from the lifters I don’t think, cause I heard plenty of that on my old 2009 burb.
I’m certainly not a mechanic, but I’ve chalked it up as normal for now. It’s noticible though. Almost like the buzz/whine of a power steering pump that is held all the way to one side for a split-second. ??