The AEM bypass valve only works if the filter is completely submerged in water. The majority of cases where people have hydrolocked their engines have been due to submerging their filter entirely in a pool of water. With the bypass valve, this same situation would be avoided.

Because of this fact, people have been quick to point out that splashes of water on the filter element are not prevented from being sucked into the engine by the bypass valve, and hence, the use of the bypass valve is often discredited. However, I would think that it would be EXTREMELY difficult to hydrolock your vehicle if water merely splashed on the filter element. One could even go so far as make a physics argument as to why a partially submerged filter will NOT suck up water. Even so, it's common sense to avoid puddles, and to let the car "dry" before taking off after you've gone through a large puddle.

So for all practical purposes, the AEM bypass valve prevents you from ruining your engine by driving through large puddles of water. IMO, if you are really concerned about hydrolocking your engine, get the Icebox. The filter will be nowhere near water. Furthermore, hydrolocking the icebox would require you to go WOT through a lake.

Shingo