omega

this has happened before but i can remember what caused it .. after car sets a while (two weeks or more) i get a loud chirt from the engine bay and only once i checked and no wildlife there

Macster

Can be a momentary slip of the serpentine belt. How old is the belt? It might be due to be replaced. If you leave the car outside dew can gather or if the car was washed and the engine not run afterwards the belt is wet and can slip and in some cases -- I notice this when I start the engine after a washing of the car -- I hear a chirp or even a faint squeal as the belt sheds the water and regains its grip.

In one case the engine was quiet at start up but after idling a moment or two it would start chirping. This proved to be a bad idler roller/tensioner bearing. I had all replaced. This is the 2nd set, too. The ones on my Boxster are original and have covered 296K miles while the Turbo has gone through 2 sets in under 138K miles.

Carlo_Carrera

Probably a loose spark plug.

https://rennlist.com/forums/996-turb...up-solved.html