Heres what my 4.0 is sounding like from inside the jeep. Its only at idle and will speed up with the rpms, can't be heard over 10mph. Im thinking its one of the pulleys but someone asked if it was a knock. Not sure!

 

I don't think it sounds like a pulley but that's just me. It sounds more like somethings loose. But it sounds too slow to be a lifter.... How loud is it from outside? About the same?

 

Sounds a little more harsh outside. Heres a vid, listen for that same noise. Hear it most under.

 

Stretched timing chain? it's hard to tell. Maybe it is a pulley. Man this is why I hate raddles hahaha.

 

Yeah it sounds loudest from the timing chain area, but wouldn't there be more symptoms if the timing chain was stretched? Just wondering.

 

Stretch is not usually noticeable, when it skips a tooth you will know. The 4.0 I have to say is the noisiest motor I have ever owned, hard to pinpoint noises with all the ticks and knocks it makes.

A cheap mechanics stethoscope is what you need to pin point engine noises. My dad was a mechanical engineer and bought me tools for bdays and christmas, this was one of the first tools he gave me. 35 years later, I really need it now. Even a long piece of tubing/hose will work to. You can leave hose open, good for vac leaks, or put a bolt in the end and touch a part to hear it more cleanly.

 

Inside it sound like piston slap just muffled, to me. outside there is too many noises to really decide.