Dont apply sealant to an o ring or a dry seal. Some seals are so thin you could easily damage them when you rip off the packaging.

Permatex Water Pump Amp Thermostat Rtv Silicone Gasket Maker
Water pump gasket sealant or not. He shows where sealant should be applied on certain gaskets and in what amount. Highest water glycol resistance available in an rtv silicone. Permatex water pump thermostat rtv silicone gasket maker a non corrosive sensor safe rtv silicone gasket material formulated specifically for water pumps and thermostat housings. Water pump and thermostat housings part 22071 i used it and its great stuff. If your new pump comes with a seal make sure its in impeccable condition before installing it. When changing a water pump replace all old gaskets and seals with new ones.
If it is not used the gasket will become wrinkled or possibly fall off during install. Permatex 22071 water pump and thermostat rtv silicone gasket 05 oz 05 ounce. Fel pro ase certified master technician john gurnig provides examples why most fel pro gaskets do not require the use of sealant. Permatex makes a specific gasket sealer for your water pump gaskets. Usually sealer is used to hold the gasket on the water pump. A noncorrosive sensor safe rtv silicone gasket material formulated specifically for water pumps and thermostat housings.
In certain cases however it is required when mating gaskets or filling gaps. Highest water glycol resistance available in an rtv silicone. It can be applied randomly and not really needed.