Astra GTC J 1.4 Turbo strange engine noise

Astra GTC J 1.4 Turbo strange engine noise
Edit: It was an unscreewed spark plug. :D

[sarahcashman]

Had exactly the same noise. All spark plugs loose. Tighten up and noise as gone thank you so much

[deborahhenderson]

Right ok, your diagnosis was correct by the way, I have same noise but only when engine hot and at tick over speed with the heated rear screen on and fan blower switched on to put engine under load for noise .
The best way to find noise is remove plastic top engine cover that has eco tech on and smell around the top of coil pack that cover spark plugs ! You will be able to smell exhaust type fumes due to a spark plug being slack and the gases being forced past the plug hole and up through coil pack ! Number 3 cylinder plug slack for me slightly ( nipped them all up ) noise gone,
Please note, this type of noise can very easily be mistaken for a water pump bearing that makes same noise when engine hot and also the ribbed alternator/ water pump/a/c belt, all common on this type engine as also the dual mass flywheels on clutch side but they normally make a clunking noise on start up ( more so when hot )
You would not think that a slack spark plug could make that noise !!! Amazing

[Incaboys]

Spark plugs are loose, check and tighten to tolerance. I hope this helps

[reallyaugmented]

100% was a loose spark plug in mine. Sound got progressively worse over a few days, mainly when accelerating at low revs. Sounded line a shot bearing behind the engine block. I removed the coil pack and the spark plug in cylinder four was only finger tight.

[deborahhenderson]

What !!! New valves fixed it ?, do you mean the cylinder head was removed and new inlet/ exhaust valves fitted

[ahmedmansour]

Please buddy, more details please I have the same noisy sound. And every time every mechanic says something different.