noisy V8

Dec 29, 2004 5 Replies

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.


Noisy lifter, change the oil.

Nowt to worry about.

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

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

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

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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