Engine clunk when switched off

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Thu 28 Aug 2003 22:23
Engine clunk when switched off - Drb
Hi,

Quick question.

My diesel Renault Trafic camper van has attained a clunk noise when I switch on/off the engine ignition. It happens more when the engine is switch off, as if 'something' is taking a second longer to stop - it also makes the engine judder slightly.

It originated when I switched off the engine and let it roll to a stop, (i.e.. not bringing the vehicle to a halt first and then switching off the engine).

This may be a silly question but in doing the above, could I have caused some damage to the engine or knocked out the timing - is it possible to knock out the timing in a vehicle.

Hope someone can advise before I take it to a garage.
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Thu 28 Aug 2003 22:40
Engine clunk when switched off - Daz
Sounds like you are pre-ignitioning.

Your van probably just needs a good service.
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Thu 28 Aug 2003 23:05
Engine clunk when switched off - DL
Engine mounting?

Don't worry, coasting to a stop will have done no harm whatsoever.

If the timing has slipped, you would know about it in different ways, believe me.
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Thu 28 Aug 2003 23:08
Engine clunk when switched off - Dizzy {P}
DRB,

I think that all you did by switching off before coming to a stop was to cut off the fuel supply to the cylinders. Since almost all the fuel is cut off anyway when you take your foot off the accelerator pedal I can't see that you could have caused any damage. No fuel to the engine simply means that the engine is turning as normal but producing no power.

That's assuming that you didn't leave the vehicle in gear right up to coming to a stop, in which case I suppose you might have wrenched an engine mounting due to a severe engine shake.

I assume Daz is thinking you have a petrol engine when he suggests pre-ignition. I doubt if this can happen with a diesel.
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Thu 28 Aug 2003 23:20
Engine clunk when switched off - Daz
Yes, my mistake forgot he said it was a diesel!
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Thu 28 Aug 2003 23:25
Engine clunk when switched off - DL
Diesels cannot pre-ignite, it is all down to injection timing.

Only petrol engines pre-ignite.
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