406 diesel turbo

everything was running fine until the other day, the car started fine
as usual and ran perfectly for about 30sec and then developed a very
loud knocking noise (sounds like its coming from no 1 cylinder area).
the car still drives as it should(done 127k) with no lack of power just
the extra noise and a slight increase in smoke. i have been advised
that it could be diesel knock but have no idea what i can do to cure
this . what do i look for and is this a common problem on 406s? i am by
far no petrol head or diesel head and would appreciate any suggestions
to cyre the knockin

 

Sounds as if the injector for one cylender has sarted to drip slightly,
which will cause a pre-ignition knock.
If you are feeling brave, then all you have to do, while the engine is
running, (I assume you can hear this knock at tickopver?) slacken the nut on
the top of the injector which holds the metal fuel pipe. Fuel will leak out
a bit, and the engine will start to miss a little, but the knock will also
go away if you have tried the right cylender. If need be, do the same for
each injector in turn.
If this does cure the knock, then first of all try some diesel injector
cleaner through the system, and if that doesn't work you need to find a
diesel injection specialist who will recondition the injector.

 

Could this be failure of the crankshaft pully (drives the auxilliary belt)?
Mine has just failed - sounded like cylinder knock for a while, then a
loose baffle, eventually failed on the motorway on Bank Holiday Monday! I've
been told this is a common fault, with the outer part of the pulley breaking
away from the middle bit.

Checking the web tells me that this pulley should be replaced with timing
belts!

AMF