C8 2.2 Petrol Engine Noise

[Guest c82.2petrol]

I have recently purchased an 03 C8 exclusive captian's 60k on the clock FSH and everything seemed to be working OK, however after a couple of days I noticed when you first started the engine it sounded like a diesel, this lasted a few seconds and then went quiet, concerned I have had a full service (that was due) including an oil flush, but this is slowly getting worse lasting longer before the noise stops, a friend suggests that this could be a sticking hydraulic valve, does anyone have any suggestions or experiences, I am concerned that this is starting to sound v.expensive.

 

Thanks