I recently got a 06 Explorer with the 4.6L V8. It has 170,000 miles on it and when I got it the engine was noisy but there wasn’t any knocking. A couple months ago I’ve started getting a knocking from the passenger side valve cover that sounds like a lifter knocking. I know it has cam actuated valves but that’s what it sounds like. The sound has gotten louder over time and it doesn’t go away when the engine warms up. I used a mechanic’s stethoscope to verify it’s coming from that area. I just found out that the shop that changed the oil last used 10w30 and based on my research it sounds like this may have caused one of the lift adjusters to fail.

My question is if this is most likely the cause of the noise I’m hearing or could it be something else? Am I over reacting to the wrong oil being used? If it is the cause is this something I can fix myself? I’m fairly crafty but I don’t have any specialized tools for adjusting cams and timing. Has anyone done a write up on doing this repair? Thanks!!

 

10w30 will not cause that problem, no matter how many ignorant comments you see all over the web about using anything but 5w20 causing the apocalypse.
I'll bet you have either one of a couple of issues with it. That'll be a 3V 4.6L in that Explorer,and it's either a bad follower(rocker arm), or a collapsed lash adjuster(lifter). Pull the cam cover and look it over.
JL