Possible timing chain woe

[katsov]

185k on my 4.0
Just recently got a steady and loud ticking that increases with RPMs. Not super noticeable at idle, but definitely hear it while accelerating. mostly sounds like coming from the rear. Plan to drop the oil pan and check for metal/plastic, but everything runs fine, so maybe it's just the tension.
Regular full synthetic oil changes since buying with 110k miles

 

[Explorer_PL]

let us know what you find out after dropping the lower pan.
I was wondering what you can see without just the bottom part.

 

[katsov]

Nothing in the oil pan to indicate broken cassette. I've also determined that the ticking only occurs with throttle change, not RPM change. I hear it as soon as barely pressing the gas before RPMs go up, and it goes away after letting go of the gas even at higher RPMs in low gear. The sound intensifies with more press of pedal

 

[gdgiordano]

The pieces of plastic from the cassette usually show up in the oil pick up under the pan. Check your harmonic balencer? I bet it’s a belt accessory.

 

[michael loibl]

Exhaust leak? Maybe at the manifold gasket?