Knocking sound M62 engine.

> wrote in message
news
> When I start from cold my V8 makes a grumbling noise like an old car
> with a bearing rattling before the oil got to it.

This will be hyraulic tappets before they fill up with oil. Be gentle for a
minute or two until they fll up and the ratlle goes away. Not normally
anything to worry about.

> Now I notice a soft
> clonking sound 2-3 times a second on tick over. The car has done 61K
> miles and has been serviced correctly. Anyone got an know what this
> could be?

Dunno - does it matter if you are in gear or neutral?

> pete
> --
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>
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>

R. Mark Clayton wrote:
> > wrote in message
> news
> > When I start from cold my V8 makes a grumbling noise like an old car
> > with a bearing rattling before the oil got to it.
>
> This will be hyraulic tappets before they fill up with oil. Be gentle for a
> minute or two until they fll up and the ratlle goes away. Not normally
> anything to worry about.
>
> > Now I notice a soft
> > clonking sound 2-3 times a second on tick over. The car has done 61K
> > miles and has been serviced correctly. Anyone got an know what this
> > could be?
>
> Dunno - does it matter if you are in gear or neutral?
>


Tappets can clack or tick especially if the car has been standing for a
while. It sometimes needs a good period of running to get them back up
to pressure (as is described in the BMW TSB)
A clonking is more worrying - some of these engines had problems with
the oil pumps bolts coming loose and if they drop out or the oil isn't
getting around the engine then thats not good.
Sometimes exhaust leaks can also let out the sound of the engine so
check for that too.

wrote:
>
> It makes no difference. I had considered a cam follower or even a
> patch on the serpentine belt as it is such a slow knock. I am going to
> the repair shop tomorrow as there are one or two other little niggles
> that need attention soon.
> pete
>

If you could relate the knock frequency to engine rpm that would help.
I.e. once every revolution, or twice, or not really related etc.

wrote:
> >If you could relate the knock frequency to engine rpm that would help.
> >I.e. once every revolution, or twice, or not really related etc.
>
> I can only hear it at tick over. I took it to the repair shop today
> and he says it is harmless tappet chatter thank goodness:-)
> pete
>
>

So He must be right :-)

If you count the number of knocks in a minute then compare that to the
idle speed then you can work out whether it's crank or cam related.

If it's 3 times per sec at low idle then that's about one knock every 4
rotations of the engine.