2.0l HDI 90 Knocking on deceleration.

[pigboy306]

Hi i have a quite noticeable noise on deceleration. The noise sounds like a knocking from the front of the engine. Connected to PP2000 but no relevant errors coming up. Hoping someone in here will have an idea. The engine has covered 112000 miles.
I did find a shard/sliver of metal in the Aux drive belt (one which drives the alternator etc) don;t know if that is connected, it was originally near the air con compressor.

[8Jb9]

By deceleration do you imply engine braking, or any sort of braking (neutral + pedal)?

If it is tied to engine braking you might want to have a look at the engine mounts. Don't know if yours might have some DMF or similar where it could knock when you reverse the force. If it is tied to the pedal then it seems more obvious to see if perhaps the pads are still correctly fitted.

Perhaps someone more familiar to the HDi can chime in with known weak points.

[steve_earwig]

Crank pull disintegrating is a killer on these but I wouldn't have thought you'd only hear it on deceleration. That's what I'd worry about seeing that shard anyway. Maybe engine mounts.

Knocking constant at engine speed, road speed, just the once?

[pigboy306]

Thank for the prompt replies. The knocking occurs moving and stationary so put it down to the engine. Bonnet lifted I pull the throttle up the engine wind up, let go and the knocking starts. No noticeable loss in power when driving, but then these aren't Bugatti anyway!

Whats Crank pull disintegration?

[steve_earwig]

Sorry, crank pulley, I have fingers like bananas...

[pigboy306]

Ahh did find a posting about that... did sound quite loud from the engine front but with all the noise i wont rule that out.It that sounds cheaper than some other options!