Astra engine noise?

Its pinking... a known fault with the 16 valve, I had the GM rep out to mine and a ECU firmware update was carried out and although it has helped it greatly it can still be heard under certain driving conditions.

Hydraulic tappets.

Do an oil change but do it the following way..

Before you take any oil out, put about half a litre of automatic transmission fluid in the engine - yes seriously.

Run for around 10-15 minutes.

Drain all the oil and change as normal.

The detergent in the ATF cleans out the varnish and other gunk in the tappets and usually shuts them up if they're not too bad.

Conor gurgled happily, sounding much like they were saying:

I think I'd rather pay the extra for a bottle of engine flush.

Flushing the engine in the 900 after doing the HG is what _started_ the damn tappets off. Barely noticable after a thousand miles on the new oil, from cold start only. So I changed the oil again, thinking I'd left a bit of flush in there. A bit more noticable, after a few hundred miles. So I changed the oil again. More or less straight from the change, quite noisy after start-up until it's had about 30seconds driving, then dead quiet until it's started after sitting for a while...

I suspect the build up of varnish and gunk is what was stopping the oil draining out of one or more...

Try good quality fuel first.

Wouldn't tappets be noisy at idle too?

It doesn't sound like any pinking I've ever heard before. That's a noise I'm very familiar with - I drive Minis most of the time!

asahartz gurgled happily, sounding much like they were saying:

In my case, just from first start-up, until the pressure builds up in them - and even then, only with a bit of load on.

Heatshield.

I listened to this with the engine hot after a run. Apparently it's the same cold too.

Doesn't sound like that - I'm sure I'd have spotted that one.

Won't be the first time dirt has been the only thing holding an engine together..