Discovery 2 V8 engine knock

Hi,

I have a 2000 Discovery 2 V8 with 51.000 on the clock.

A couple of weeks ago in the very cold weather I noticed an engine knock
after starting. What happens is, I start the engine in the morning, no
problem, no unusual noise. I then put it in gear (auto) which reduces the
engine speed and loads the engine and it starts to knock, take it out of
gear and the knock stops. running the engine for a couple of minutes means
you can drive away, no knock, no problem for the rest of the day.

At first I thought it could be a hydraulic tappet issue but the knock sounds
a bit deep for that although I would be quite happy if someone says that is
how they sound.

Any thoughts?

--
Pete Aldous

http://www.stationaryengine.org

"Pete Aldous" <[email protected]> wrote in message
news:[email protected]...
> Hi,
>
> I have a 2000 Discovery 2 V8 with 51.000 on the clock.
>
> A couple of weeks ago in the very cold weather I noticed an engine knock
> after starting. What happens is, I start the engine in the morning, no
> problem, no unusual noise. I then put it in gear (auto) which reduces the
> engine speed

It shouldn't reduce the speed, the idle speed control circuit ought to
maintain the correct speed. Mine certainly does, 2000 4.0V8 XSi Auto.

> and loads the engine and it starts to knock, take it out of gear and the
> knock stops. running the engine for a couple of minutes means you can
> drive away, no knock, no problem for the rest of the day.
>
> At first I thought it could be a hydraulic tappet issue but the knock
> sounds a bit deep for that although I would be quite happy if someone says
> that is how they sound.

Mine has a very quiet soft "knock" until the engine is up to full working
temp, it's a know issue caused by the slight play in the camshaft
keeper/retaining plate, as the engine doesn't have the camshaft held back
against the block by the thrust from the mesh of the gears driving the oil
pump, due to the different oil pump and drive design. That's not to say that
your knock is the same thing though....
Badger.

"Badger" <[email protected]> wrote in message
news:[email protected]...
>>
>> A couple of weeks ago in the very cold weather I noticed an engine knock
>> after starting. What happens is, I start the engine in the morning, no
>> problem, no unusual noise. I then put it in gear (auto) which reduces the
>> engine speed
>
> It shouldn't reduce the speed, the idle speed control circuit ought to
> maintain the correct speed. Mine certainly does, 2000 4.0V8 XSi Auto.

Thanks for the response.

Mine has always run at around 150 rpm faster for the first 30 secs in the
morning from new and then settles down so putting it in gear before that
results in loading the engine which produces the knock. The same knock is
audible if you drive off imediatly after starting the engine but only for
around 50 yards.

> Mine has a very quiet soft "knock" until the engine is up to full working
> temp, it's a know issue caused by the slight play in the camshaft
> keeper/retaining plate, as the engine doesn't have the camshaft held back
> against the block by the thrust from the mesh of the gears driving the oil
> pump, due to the different oil pump and drive design. That's not to say
> that your knock is the same thing though....
> Badger.
>
My knock has only started in the last couple of weeks and completely
disappears after about a minute as if, once the oil fully circulates it
stops the knock.

--
Pete Aldous

http://www.stationaryengine.org

Maybe you need new or thinner oil and a new filter???


"Pete Aldous" <[email protected]> wrote in message
news:[email protected]...
>
> "Badger" <[email protected]> wrote in message
> news:[email protected]...
> >>
> >> A couple of weeks ago in the very cold weather I noticed an engine
knock
> >> after starting. What happens is, I start the engine in the morning, no
> >> problem, no unusual noise. I then put it in gear (auto) which reduces
the
> >> engine speed
> >
> > It shouldn't reduce the speed, the idle speed control circuit ought to
> > maintain the correct speed. Mine certainly does, 2000 4.0V8 XSi Auto.
>
> Thanks for the response.
>
> Mine has always run at around 150 rpm faster for the first 30 secs in the
> morning from new and then settles down so putting it in gear before that
> results in loading the engine which produces the knock. The same knock is
> audible if you drive off imediatly after starting the engine but only for
> around 50 yards.
>
> > Mine has a very quiet soft "knock" until the engine is up to full
working
> > temp, it's a know issue caused by the slight play in the camshaft
> > keeper/retaining plate, as the engine doesn't have the camshaft held
back
> > against the block by the thrust from the mesh of the gears driving the
oil
> > pump, due to the different oil pump and drive design. That's not to say
> > that your knock is the same thing though....
> > Badger.
> >
> My knock has only started in the last couple of weeks and completely
> disappears after about a minute as if, once the oil fully circulates it
> stops the knock.
>
> --
> Pete Aldous
>
> http://www.stationaryengine.org
>
>