Rattle.. and its not the timing chain

[amdmaddness]

I have a 2002 Mountaineer with aprox 207,000 miles. The timing chains/guides have been replaced approx 80k miles ago.

Here is the issue: I have a slight rattle on the front of the motor. I have replaced the tensioner, the idler pulley, Serpentine belt, and the harmonic balancer. If I remove the Serp Belt the engine runs completely quiet and rattle free (thus eliminating the chains/guides). Does anyone have any ideas? I am thinking maybe water pump but that's been replaced a few years ago (but may be the issue). Even the new tensioner bounces a bit but not more than a usual one would, the noise sounds like it emanates from the tensioner but it has been replaced three times now. Ideas?

 

[2000StreetRod]

same problem

I have the same problem - rattle is intermittent (sometimes in Drive and sometimes in Park). I have checked the balancer and replaced the serpentine belt, the tensioner pulley (not the entire assembly), and the water pump. I'm planning to upgrade the alternator and wonder if that will make a difference. I'll also replace the entire tensioner assembly since the rattle seems to come from that area after listening with a length of flexible hose.

 

[luisabad]

Add me to this list. 2002 Ex with 179K. Same rattle, belt tensioner jumps a little, sometimes it stops for a few minutes. Replaced idler pulley, belt tensioner and no change. When I start it cold in the morning you can hardly hear it, gets louder as it heats up. I suspect the alternator but since its charging ok I'm not wasting money until it breaks down.

Let us know if replacing the alternator made any difference or not.

 

[amdmaddness]

It ended up being my water pump. I took off my belt and there was play/wobble in the pulley. Replaced the pump with a bosch unit and all is fine now.

 

[gsbarry]

Let's revive this old thread... I have very similar symptoms. 4.0 SOHC w/ 200k on her. Rattle only presents when warm and idling in drive and w/ A/C on - so could be A/C pulley for sure. Rattle noise itself though seems to come from tensioner - replaced twice recently to be sure. I can press the tensioner with an extension while running and this stops the rattle noise. Question is what is making the new motorcraft tensioner rattle? Water pump has been replaced recently and I did not observe a change in symptoms. Running without the belt for testing purposes doesn't seem to be an option since the rattle only presents when warm. Not 100% sure this isn't transmission of timing chain vibration through the belt tensioner, but even then this is the wrong location for timing chain rattle), doesn't sound like a chain to me, it is so intermittent - only at closed loop (warm) idle under load.