Lubrication of o-ring seals is extremely important for the installation and operation of dynamic seals as well as the correct seating of static seals.
Super O-Lube is a silicone
lubricant that can be used with virtually any rubber polymer over temperatures
ranging from -65°F to +400°F. Used sparingly, it will provide better
environmental protection for the elastomer. It is particularly recommended for
high pressure systems, as well as vacuum applications.
Super O-Lube is available in a variety of package sizes for use in kits, tool boxes, and more.

A video that shows how to lubricate an O-Ring is avaialble to view here.