I have this weird noise while idling. Doesn't happen all the time and goes away with the RPM going up. Engine runs fine. Has 135xxx miles on it. It's not the ticking noise. I believe that's injectors?
Mine developed a noise almost similar to this back in April, thought the oil was low and the dipstick was reading full. A month later towards the end of May, DoD Lifter #4 collapsed on a road trip after stopping for the night. When I got the truck back from the dealer the noise was gone.
I'm with @Mooseman on this... and the video below will show you a running engine that sounds almost like yours does ...and Brian also tells you exactly how to deal with the problem. But make sure you watch the ENTIRE video, so you don't get discouraged when he discusses the need for "pulling the cylinder head"...Because ultimately, his Alternate Approach to the Fix WORKS GREAT ...is very well described ...and will be easy for you to do yourself:
Nope. They're hydraulic so self adjusting. If it's a bad lifter(s) though, you have to remove the head(s). I'm on the middle of doing that now. Mine sounded like a sewing machine between 2-3000 rpm. Ran fine. Swapped cam, lifters, rockers, etc.