motor rattle

[pas121268]

i have a 2002 with a 4.0 and an unexplained "rattle" in the motor. what i have done, thinking it was the idler or tensioner is replace both, no luck. then i removed the serpentine belt to eliminate all external bearing sources. still had the rattle. the rattle doesnt sound like a rocker that ive heard before because the rattle is not constant, very intermittent. really sounds like a loose piece of sheetmetal bouncing around inside the engine.

 

[Swamp Fox]

Sounds like it might be the chain tensioner for the timing chain.

 

[Number4]

Second that ^^^.

If it's constant, that's not good. Means you have run out of 'borrowed time' so-to-speak.

I'd have a shop look at it really soon. If you are mechanically inclined and don't mind pulling the engine to do the work, you can take a peak.
Pull the valve covers, when the engine hasn't run for a while, see if the chains have any slop in the. Also see if the guides are broken.

 

[Tech By Trade]

Welcome to cam chain tensioner ville. Open your chequebook. Its gonna cost ya!