Knocking noise when switching off engine

Any advise/help welcome.

Around 8 out every 10 times when switching off the engine there's a light to medium knocking which feels very like the engine is running-on or moving around possibly not shutting down properly. I doubt it is running-on, modern fuel injection cars shouldn't suffer from this, a phenomenon anyone old enough to remember carburettors and points might remember.

Thinking (and I still suspect this) its an engine mount issue I've replaced the dogbone mount... no improvement, although grabbing the engine close to timing belt mount results in a fair amount of movevent.. to me anyway. We also have 2006 1.4 clio essentially similar renault generic parts engine block etc. with no where near as much movement from the same engine mount.

Is failure of any of the top mounts a common problem?

Other possibilities would be something around altenator, a/c commpressor, crank damper or the renault vvc device.

Car has only done 23,000 miles being a 2010 plate, well maintained annual oil changes using top quality oil.

Tom

Hi tom I can't be 100% with out actually seeing for myself, but the mounts could well be your problem. Think it would be best to replace all the mounts they really are crap, only knocking issue I've had was when the upper gearbox mount pin snapped and the gearbox was knocking on the subframe as a consequence. I've updated my dog bone to a vibratecnics and got a power flex engine mount void bush for the 182 which are exactly the same mounts to the twingo rs. The reason the upper mount goes which your talking about is the buffers wear out and the fluid inside can leak aswell. How's the clutch uptake is quite hard to feel the biteing point, & are you getting much kangoorooing due to sloppy mounts.

Thanks for help, mounts would be a logical place to start.

My wife drives it much more than me, but I've not noticed any serious juddering or excessive engine movement pulling away. Similarly clutch take up feels ok. Very odd.

There's definitely too much movement in the top (hydraulic) mount for sure. Was thinking on jamming some hard rubber blocks temporary each side of top mount and see if issue stops I'll take a quick look at the vibratecnics mount, which is similar in concept.

Tom

Quick update,

tried loading up the engine in 1st gear clutch at biting point (while parked up). Swich off .... no knocking noise. Repeat in neutral, switch off knocking from around top rhs (from drivers seat)

So... I'm now definitely thinking engine mounts?

Think that's the first thing to eliminate mate, if like you say the mounts shot anyway may as well get that sorted then go from there. Febi ones can be had for £20 off fleebay easy enough to change if you have a jack to support the engine underneath.