Engine Oil - Smell of Petrol

[Geezer-20v]

Hi all,

Ive just been doing some maintenance checks on my car (Seat Leon 1.8 20v 03 plate) and while checking the oil level the dipstick smelt of petrol. I put my nose the dipstick hole but could not smell anything.

I take it this is not right and im guessing a piston seal or something has gone.

Anyone had this before? What is the most likely cause of this? Is it an expensive fix?

Cheers