[l33r3n33]

Started my vehicle only to hear a tapping…..I opened the hood and found the source area of the sound. Seems to be coming from underneath around where the turbos are where the hpfp is? Ideas?
Recently had my rocker arms replaced. Could it be those?

 

[FMCSMT]

If it sounds more like a thumping noise, remove the air filter and listen. If you can clearly hear the noise through the air inlet then most of the time it is a valve train issue. A valve train issue being rocker arms, valve bridges, bent push rod, seizing lifter.

 

[yan7gin]

does it do it as soon as you start the engine or take a bit of time... does the truck rev over 1700-1800 rpm?