noisy V8

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gazza - 29 Dec 2004 22:17 GMT

Yesterday morning I started my 1998 4.6 P38 for the first time in several
days.
All was normal until as I pulled away a nasty loudish knocking or more like
a clacking noise came from the engine. Easing off the throttle made it go
away. A bit more welly and it returned. I pulled over, put it in neutral and
it sounded ok even with increased revs. After 2 minutes with my head under
the bonnet I put it in drive and tried again, now the noise was gone. Since
then it's not done it again. Any of you V8 experts got any suggestions what
this may have been? It's done 91k, doesn't loose water or oil apart from the
usual oil drips on the floor and generally seems in good nick.

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gazza

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1987 RR Classic
1998 RR P38

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SimonJ - 29 Dec 2004 23:42 GMT

> Yesterday morning I started my 1998 4.6 P38 for the first time in several
> days.
[quoted text clipped - 6 lines]
> this may have been? It's done 91k, doesn't loose water or oil apart from the
> usual oil drips on the floor and generally seems in good nick.

Noisy lifter, change the oil.

Nowt to worry about.

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Alex - 30 Dec 2004 00:39 GMT

>Yesterday morning I started my 1998 4.6 P38 for the first time in several
>days.
[quoted text clipped - 6 lines]
>this may have been? It's done 91k, doesn't loose water or oil apart from the
>usual oil drips on the floor and generally seems in good nick.

Hydraulic lifter gotten a bit clogged I expect. Flush the oil and fill
it with some fresh, otherwise don't worry about it. They sometimes
take a bit to pump up fully, especially if it's been left for a few
days.

If you start getting it regularly then you might be looking at a new
set of lifters, but I suspect you won't hear it again.

Alex

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gazza - 30 Dec 2004 10:55 GMT

>>Yesterday morning I started my 1998 4.6 P38 for the first time in several
>>days.
[quoted text clipped - 5 lines]
>>it sounded ok even with increased revs. After 2 minutes with my head under
>>the bonnet I put it in drive and tried again, now the noise was gone. >

> Hydraulic lifter gotten a bit clogged I expect. Flush the oil and fill
> it with some fresh, otherwise don't worry about it. They sometimes
[quoted text clipped - 5 lines]
>
> Alex

Thanks for your suggestions.
Would a sticking lifter only make the noise when the engine is under load?
In November a local LR specialist did a service that included an oil flush.
I remember someone on this group saying not to flush as it could dislodge
crud and cause blockages.

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gazza

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1987 RR Classic
1998 RR P38 ex Jamie Redknapp

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Alun P - 30 Dec 2004 07:06 GMT

I had the same problem on my 3.9 which manifest itself after the engine had
stood for a day or so. Noisy ticking until the engine warmed up.
I changed the oil after using a lifter flushing agent, from Wynnes I seem to
remember, new oil and all OK.

AlunP

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Ekoms - 30 Dec 2004 08:59 GMT

The fact that it only does it on load and not in neutral with revs
suggests that it may be a loose or cracked drive plate on the auto. The
drive plate is what the torgue converter bolts to and if the bolts are
loose it will give you the sound you mentioned.
One test you can try is to put it in reverse and accelerate firmly and
then back into drive to see if you can reproduce the noise.
I am not sure on the 4.6 but there may be a dust cover you could remove
and check the bolts for tightness.
Also if possible you could crank it over without starting and see if you
can hear the noise, if so it's definately not a lifter.
Hope this helps
Ekoms

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