Ok people - some basic physics here - water is heaver than air - that's why it's on the ground
- a defender has the air intake on the side of the wing , around half way up.
Therefore logic dictates that if you have the bonnet under water this will be as well.
As I'm sure some people have found out the hard way, a diesel engine sucking in air (+/-a turbo adding another 0.5-1.5 time negative pressure to this) is going to suck in whatever is on the outside of the air intake pipe. Therefore clearly if this air intake is under water (see above) you are going to suck water in.
Thankfully this water will stay at the bottom of the pipe, and firstly fill up the air filter box and the lowest point of the it intake system and keep filling up until this lowest point is full/ it reaches the level of the intake manifold, by which time it gets propelled into the cylinders. Piston then comes up and tries to compress water (wwhich students of physics or chemistry will know is incompresible) this then causes the obvious distruction of the engine.
Bottom line is that if your claimiming it was over your bonnet and you did not have a snorkle fitted, some or all of the following are correct
1) the water depth was not infact that deep and it was just the bow wave comming over the bonnet
2) You'r incredably stupid
3) You like rebuilding engines
4) Your engine is nackered.
Comments on a post card please