Air Filter and Water on FG

[gait]

On an FG I bolted the air filter housing back onto the chassis yesterday, needed access to something else. Air intake is above and behind cab. Filter at fuel tank level.

Noticed that there are two simple soft rubber "non-return valves" about 1 1/2" diameter in the bottom. One below the center of the filter, another below the vertical inlet.

How effective are they if driving through water? Do I need to seal them?

 

[1Engine]

I am always paranoid with these ejector valves.
They need to be soft & flexible & where they seal need to be clean.
I had a mate that had his hilux ute hydraulic due to the during cyclone justin, rain blew in the snorkel & filled the engine with water due to the valve did not allow the water to drain.
In earthmoving equipment they should be checked, flicked everyday- yeah sure. It is the same that the wiper blades on trucks should be flicked daily
Personally I dont trust them, that is why my air cleaner is above chassis level