328 Engine tapping on Cold Start

328 E46 1999 80K Miles
Had from new, very few problems.
I have noticed over the last few months that when starting from cold there is a light metallic tapping from the top of the engine for a few
seconds directly after starting up which then disappears.
Please could you tell me what this is ? Is it serious ? Can it be fixed ? Does it need to be fixed or is it just a sign of old age creeping up ?
Thanks in advance for any help given.
Mal Vicars.
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There is a part, 24 of them actually, called a lifter. It's job is to play interference between the cam lobes and the valve stems. These lifters use oil internally to cushion the meeting of the valve and the cam, and what you are hearing is the lifters making a bit of noise before they get any oil.
It is not serious, usually. It can be fixed (sometimes) with an oil additive that removes the tarnish inside the lifters so that they don't stick on themselves. (A lifter has a spring and a piston - for lack of a better word - that move against each other, they get sticky and this results in slop that you hear as a tick.) It can be a sign of old age. Back in the olden days, we used to pour in automatic transmission fluid into the engine. the AFT is very highly detergent and it will clean the gunk from the inside of the lifters, the downside is that it has been known to make a hard seal -- which should be soft -- even harder and more brittle, and this can result in a leak later on. Today, there are products like Marvel Mystery Oil that are detergent, but no so hard on the rubber seals. You might want to look at these kinds of products - they cost more than ATF and I have no idea if they actually work any better.
When you get the ticking squared away, you can keep it at bay by changing your oil more frequently. Old, dirty oil is the biggest cause of sticky lifters.

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Most likely the hydraulic tappets. These automatically maintain the clearance between valves and camshafts.

No - it could run for many thousands of miles without getting worse. And even if noisy all the time - and not just at start up - the engine can still run perfectly well.

Yup. They can be replaced.

I'd not bother, until they are noisy all the time.
The other possibility is timing chain slap at startup.
Same things apply.
--
*It's not hard to meet expenses... they're everywhere.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Hi Mal.
I've just repaired by E36's noisy engine - rocker covers, camshaft, and tappets. The noise, like your's, started around the 150000 km mark, or probably earlier, cannot really remember.
At least, start with an oil change and ensure the spray-bar is cleaned.
My mechanic advised that oil changes should be every 10000kms or six month, whichever comes first.
Regards,
-- Jason 8MP Australia
| 328 E46 1999 80K Miles | | Had from new, very few problems. | | I have noticed over the last few months that when starting from cold | there is a light metallic tapping from the top of the engine for a few | seconds directly after starting up which then disappears. | | Please could you tell me what this is ? | Is it serious ? | Can it be fixed ? | Does it need to be fixed or is it just a sign of old age creeping up ? | | Thanks in advance for any help given. | | Mal Vicars.
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He would, wouldn't he?
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*Strip mining prevents forest fires.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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