High Water, Flooding, and Deep Puddles, Holes, or Fording
Some years like 2014 yielded lots of snow. When snow melts flooding begins. The beginning of warm weather also signals the beginning of the Hurricane Season. I don’t have to tell those of you who live in coastal regions what that means; flooding. Being aware of how water affects your vehicle is a critical first step to your protecting your investment and keeping yourself out of danger.
You don't have to be off-roading to swamp, submerge, or hydro lock your vehicle. If you drive a car it is especially important to understand the dynamics of the basic functions of your car and how water can totally destroy it in seconds. Open the hood of your car and look at the location of your average car's engine air intake horn and you will see that it is aimed directly forward, generally a plastic or rubber hose with a funnel shaped intake horn up at the front of your grill, under your nose plate, or in a hood ram air scoop. The lower that your car is slung and your intake air horn is located the more risk you are at. Let's look at a real world scenario; you are driving and you see a large puddle, you would have to pull over and back down the highway to avoid it so you decide "it is just a puddle", you gun it and go through it, or I should say you try. As you car hits the water, the water rises up as the car displaces it, causing the height of the water to double or more, now, the water under pressure to disperse takes every route it can. One of those routes, aided by the suction of the engine sucking air in through the intake horn is into your engine. Poof !!! Disaster !!
When water enters the combustion chamber of your engine, total destruction of engine can follow in seconds. You are generally revving the engine high to get through the water, increasing the force with which the pistons are flying up and down in the cylinder. Unlike an air / fuel mixture, water does not compress and acts as though the cylinder is filled with concrete causing the piston rods, pistons and head to experience forces 10 to 20 times the normal forces of the engine. Pistons crack, piston rods stress fracture or outright break causing catastrophic failure of the engine.
If you come upon the deep water without warning and cannot stop without hitting it, there are some actions that will limit the risk of damage; if you can safely stop, do so, if not let off of the throttle (gas pedal), as you slow and the water settles if the engine is still running slowly accelerate out of the water aiming toward the lowest point, keep the intake horn side at the highest level possible.
If your engine stalls, do not attempt to start it. If water entered the cylinders you will increase the damage. If you are in the wilderness you will have to service the engine immediately after pulling the vehicle out of the water or have the car serviced immediately at a qualified ASE mechanic shop. The water can corrode interior engine components shortening their life by years. The water can also destroy sensitive electronic components.
See the section on post hydro lock engine basics.