5.7 Chevy vortec tapping noise

Answer 1

There are several possibilities, depending on what it sounds like:

• piston slap, which is common and annoying, but not something that will cause engine failure any time soon.
• collapsed lifter(s), which typically occurs when the oil is not changed at the recommended schedule. Collapsed lifters are usually an indication that OTHER things are going wrong.
• worn rod bearings... really bad. Typically there will be low oil pressure as well because the oil leaks out past the excessive bearing gap.

My 98 Tahoe was making the same type of noise, turns out it was just low on oil. Once I got it to the right level, the noise disappeared. I felt like an idiot, I didn't think it could be something that simple.

Clarification:Assuming all other things being equal, if someone allows their engine (ANY ENGINE) to run low on oil, serious damage has already been done which no doubt has shortened the life of the engine. Failure to adequately monitor the oil level was not addressed because it is so atypical.