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Discussion Starter #1
Good day fellow Alfa drivers.

My trusty 156 has recently developed a tapping noise for the first mile or two of driving, only audible when the engine reaches about 1500rpm.

The other day I opened the bonnet and had a listen while I brought the revs up and I could confirm the noise was coming from the top of the engine.

If I run the engine for a minute or two on the driveway before I pull away it's fine, so clearly once it has warmed a fraction and the oil has got where it needs to go it sorts itself out.

The sound does sound like the old tappets sound on the old OHV engines, but I know the V6 is DOHC and I know there are shims in there.

Now in your experience, would the sound of worn or misadjusted cam gear cause it to tap constantly and at all engine speeds or is it tapping only at 1500rpm when stone cold a possibility too. Are they likely to just need adjustment?

It had an oil change last summer, and the oil level is on max. It did cross my mind that I might have an oil starvation problem, but then surely I'd get tapping at idle too.

Now I try to keep local driving to a minimum but as my gf doesnt drive I have found myself having to pick her up from local addresses in the dark so it has had a few short runs. Whether this could of had something to do with it I don't know.

Any advice or tips would be appreciated before I get anyone to look at it.
 

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when was the cambelt done, as mine started with a tappety noise form cold, turned out to be the belt tensioner/idler which was worn and not oiling properly.
 

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Discussion Starter #3
Sound coming from the top though...

I don't believe it's due yet, although from memory while sitting comfortably on the sofa I couldn't quote you a figure.

However if it was the belt tensioner would the sound not be coming from down the side of the engine and not the top? Like I say I had my head under the bonnet the other day listening to where the sound was coming and it was distinctly coming from the top of the engine.
 

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Discussion Starter #5
Well, in my case it's only started doing it in the last month else I would consider it normal.

If I take it for a service I'm unclear what would need looking at... replacement, repair or adjustment.
 

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Per the thread linked above the tappets do drain down and can be clattery for a while - one of the causes is varnish build up in the drain holes (apparently).

We did an oil flush (Forte), then dropped the oil, then refilled it. The improvement was immediate - the tapping was might quieter, and over the following week went completely, and has not re-appeared.
 

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Before assuming tappet problems, make sure that its not just a noisy purge valve - it can make an awful racket!

I was sure at first that I had the same problem and tried clearing it as per the above link - no improvement. Then I thought about the same problem on my last car, a Rover, which sounded like a diesel at times as the purge valve clattered away embarrassingly!

My V6 is the same - the purge valve clatters like a good'un while its warming up then quietens down.
 

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Sorry I dont know, on the Rover 75 it was easily accessible and most owners swapped it for a good one, although apparently it wasn't doing any harm, but on the 156 its hidden away.

Try and isolate exactly where the noise is coming from before assuming either the tappets or the purge valve - if the clattering seems out of sync with the engine or irregular, for example if it sometimes gives a burst of clattering while idling, this would suggest its possibly the purge valve doing its job noisily. Like you say, its often worse on shorter trips, possibly because there are more fumes being produced by colder running.

The purge valve is hidden in the bulkhead area on the cambelt side of the engine, hence its difficult to separate the two.

I find mine is silent for the first couple of minutes, then clatters while the guage moves up the scale, then becomes silent again for most of the time with just the occasional fanfare!:lol:
 
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