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I know that hydraulic valve lifters can be a bit noisy on startup. Can they be quiet on startup and become noisy when warmed up? (VW engine).
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Not sure about the VW, but others can rattle if the oil is thin and getting a old and you thrash it a bit and the oil gets hot and thinner.
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And they can stick and get a bit slow to take up the slack as the camshaft lobe rises. There are additives and ways of flushing to deal with severe cases - not sure of any references on this one.
Does it still do it after an engine flush and new oil?
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There are additives and ways of flushing to deal with severe cases - not sure of any references on this one.
There's a product called Top End Treatment from Forté Lubricants. More details here:-
www.honestjohn.co.uk/forum/post/index.htm?v=e&t=15...4
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I've tried Wynns engine cleaner, 20/50 oil, STP viscosity improver, now on semi synthetic oil.
From cold there is no noise until the engine reaches about 4000rpm - then there is a sort of muffled tappet speed knock. As the engine warms the knock becomes a clear metallic rattle, still at tappet speed but it now starts at about 3000rpm. Under this speed the engine is quiet. If I go past 3000rpm the noise is embarrassing, and at about 4000rpm hot it becomes a metallic 'screech' and as soon as the revs drop, the noise stops.
With a hot engine I can't get a 5 thou feeler blade between base of cam and follower, yet I can still turn the follower, so clearances seem to be ok. I can't press the followers down against the residual oil content, so they seem to be ok. I've asked a few local garages to 'have a listen' and been told that I need a new engine. (no diagnosis, just replace). I'm certain that the problem is a faulty valve lifter, hence my original post.
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On my last car I had a similar thing, under load the engine started knocking. (Wasnt just above 3000 though, it was whenever the engine was under load), it turned out to be a big end bearing which had distorted slightly.
Does yours rattle ONLY over 3000? Try putting it in too high a gear and putting your foot down?
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I've asked a few local garages to 'have a listen' and been told that I need a new engine. (no diagnosis, just replace).
Sign of the times I'm afraid. No-one knows how to diagnose engine faults any more (unless they generate a fault code - most niggles like this do not).
So they either say "Sounds alright to me mate" or "Needs replacing".
Main dealers are even worse, with their "No fault code, no problem" or "Our engines are usually robust as a unit, never had a faulty one in here" bull-excrement.
An engine specialist might be able to help - if your engine is otherwise good & worth re-con'ing.
Regards,
Al.
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Would agree with the last comment, that main dealers seem to totally rely on what there computers say,having has that experience recently.Saying that it does seem to vary from garage to garage,which alone is annoying.Ones that do give a pink fluffy dice do exist as I found out(thankfully !)Oh for a mk1 Ford escort again!
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