Blower Resvoir 2006 saleen leaking through cap

This is not an uncommon problem with the early reservoirs. The problem is that the inner edge of the reservoir neck is too thick for the cap and gasket to seal properly (the fill hole diameter is too small). One fix is to add a second gasket and the cap will seat and seal. The second is the recommended fix by Saleen:

"Intercooler Reservoir Modifications:
The inner edge of where the cap sits on the reservoir is too small and contacts the plastic on the cap rather than touching the gasket. The fix is to chamfer the inner edge of the reservoir, removing about 0.200. A 45 degree angle spec is not critical. The reservoir should be removed and flushed out to ensure that no piece of the plastic get caught inside."