[3rdday]

Silicone will swell with oil and fuel, unless it is a Flourosilicone, whick you wont find. it is sold as gum stock to injection molders, use as o ring material and fuel hose liner in aerospace and automotive.
Also a big mis understanding- silicone is a terrible adhesive unless used on glass. for this application you need an adhesive and sealant.Good choice on the permatex.
Also never use silicone to seal holes- use a polyurethane such as 3m 5200 UV or Sika, Bostic etc