105Tsi DSG starting noise

[runboy]

Couple of times now the Fabia has made a mechanical noise on start up, and for a few seconds after, the note of the noise changes when I turned the climate off/on i.e. when a load put on the engine. Never heard it before until today. Difficult to describe the noise, maybe a bit like a slowly turning a tin with nuts and bolts in.

Any ideas?

[GeneralPurpose]

Watcha runboy, yep...there are plenty of things that can make the noise you describe. It may just be a loose external engine problem such as a heat shield on the exhaust and when the engine is loaded it stops the resonation. It may be a loose exhaust baffle which stop rattling when it gets hot or under load. How many miles has the car done? How long does the noise last after starting the engine? Obviously, I can't hear the noise so it's by no means certain what your problem is. However, the starter motor bendicks can also make this noise if it sticks on the flywheel ring gear immediately after startup and stops when it shakes it'self free. Hydraulic tappets can also become noisy. Usually, it's only one at a time when it becomes leaky, but that makes a loud tapping sound after start up and can last for either just a few seconds or maybe a mile or so. It's difficult to identify which one may be faulty so the set would be replaced all at once. If you have an upper engine oil pressure problem developing, this may make the hydraulic tappets all rattle a bit for a few seconds until they get enough oil but this usually only happens with large mileage on the clock as they should maintain their oil reserve during stationary periods unless it's a very long period of inactivity. Loose camchain is another potential problem. This is often an oil pressure problem so you should not ignore this noise. Get it checked asap.

Just a quick edit: it could also be an intermittent faulty oil pressure relief valve letting oil drain back into the sump out of the oil galleries which causes the engine to run slightly unlubed at startup until pressure is built up.But really need to hear the noise to be more accurate.

Edited 26 November, 2011 by Estate Man

[runboy]

Thanks EM, plenty of food for thought. Noticed it today for the first time and both times after the car had been used about an hour earlier. When I heard it the second time I turned the engine off then on again and the noise wasn't there. I'll try it in the morning after it has been left overnight and see what happens, might video it so I can capture it.

[GeneralPurpose]

A video would be good!