Hello!

Looking for help with this diagnosis from you Ford 5.4 gurus.

I have a rattling sound that comes and goes on my 99 F150 with 5.4 V8. It seems like it comes on after getting warm and only noticeable at low RPMs. It seems to be coming from the passenger side valve cover, towards the front which makes me think maybe it is a timing chain issue.

I initially had a fear that it was rod knock... but I'm doubting that since it is in the top end.

video link 1: http://www.youtube.com/watch?v=t7lyk...ature=youtu.be

video link 2: http://www.youtube.com/watch?v=Gy9OY...ature=youtu.be

There is a pulley that is stuck... but it isn't even moving so I wouldn't think it was that.

Thoughts? Similar sound you have heard before? Probably started about 10k miles ago and hasn't changed in sound since.

Thanks for the help!!

 

take a wood stick (broom handle) and place one end on the manifold and hold your ear to the other with the motor running. don't get caught up in the fan. you should be able to hear the inner motor working through the broom handle. i have an 02 5.4, and my injectors have always had a loud ticking, even after replacing.

 

Why is that idler pulley not working and tore the belt apart?
Sounds consistent with the rotating assembly...and has that hollow sound making me think it is a main or rod bearing. I would have to hear it reved. What does the sound do when reved?
Try to pin point the sound with a mechanics stethoscope (harbor freight for about $5)

You can removed the passenger valve cover while off and check the chain for any slack.
I had a similar issue with my last motor that was in the truck when I bought it. Ended up being chain tensioners and a rod bearing were bad.

 

Sounds like it's right there @ the top gear under the cover.

A few other simple things to do, to go along with what others have mentioned, -

Well, first thing to do is make sure the PCV isn't plugged. A build up in pressure under the cover COULD very well be forcing/stressing; having an effect upon components therein.

I'd run it without the belt as well, - just to confirm the noise isn't transferring from the tensioner pulley to the front cover.

 

Thanks for the input. I'm going to check the PCV... I remember there is a lot of "gunk" around it.

I'll try the stethoscope (probably similar to the broom stick) and also without the belt.

When reved the sound goes away... it is only at idle to maybe 1400 rpm that it is noticeable.

Thanks again!