Fading ticking noise from motor

Hydraulic Lifters are your primary culprit. They may be frozen or stuck with sludge/varnish. This means you can have valve lash on a vehicle that is not adjustable by a screw. Either way it really isnt a big deal and you might not have to pull the head off. There is a tool you can use to pull them out, $30 at O'Reilly and you just need to take the push rods and rocker arms off so you can get to them. Key is keep them in order.