Ive got a random noise that only occurs when ive had car parked up for a few days and engine cold? On intial start of that day when engine fires up it sounds like either a massive air purge like what you would here from a compressor relief valve crossed with a dry rotational spinning bearing, noise happens for about 0.5 sec then is completely gone and wont happen again for rest of day or even if i use it next day, leave it parked for 48 hours or more and it does it?

 

If I'm understanding correctly, mine does the same thing too. Mine is a 2002 with 69K miles. Not sure if its normal but I've always wondered as well.

 

Might be your starter, if it is, no biggie.

 

More than likely just the sticky starter.
Common in 99% of our cars

 

Ah right now youve said it it does sound like starter motor, youve jogged my memory to a friends old audi A3that used to make similar noise years ago, so aslong as noise goes within 1st second of starting like it is im ok to just leave it alone?

 

yup.