Rattle

[Nimbus117]

Hi Guys,

Just bought a 2003 2.7L, it's in excellent condition despite it's 90,000 miles. It has a rattle at the rear however which is driving me insane.

It sounds a little like valves rattling, only happens below 2500rpm when either slowly accelerating or decelerating. Of course it may not be the engine but this is when it's noticeable, cant hear it with the hood up only when it's down and road surface makes no difference.

I have had it up on ramps and checked all the heat shields, tie bars etc but nothing is obviously loose. Can anyone help? I thought it might be detonation and maybe try different fuel but it does it does it on deceleration too.

All suggestions are most gratefully received.

Thanks

Richard

[Nimbus117]

Had all the covers off the engine, nothing loose in there and I cant see anything loose anywhere else.......help!

[Loren]

I would remove the polyrib belt - check each of the pulleys for wobble and replace any that have wobble.

If none have a wobble - then run the car for a short period and see if the sound is still there.

[Nimbus117]

Thanks Loren,

Had the covers off, belt looks new - seems to be tensioned correctly and no wobble. As is only evident during acceleration or deceleration I think it's the exhaust, seen a few posts on forums about the Cat rattling. Not sure how to check this as I cant replicate the rattle by banging it - not even sure which one it is. It only does it when there is a load, revving it has no effect. I dont mind replacing both Cats but would be really annoyed afterwards if it still rattles.

[Loren]

The only way you can check for wobble is to remove the tension caused by the belt.

[Nimbus117]

Found it, both Lambda sensors on the LH exhaust were both loose. Tightened them up - rattle gone! Wonder how that happened?