What is a water hammer, how dangerous it is, how to act in this case and how to overcome deep puddles as safely as possible.

During the rainy season, drivers should be cautious and avoid deep puddles. If the engine suddenly stalls, it’s not a good sign. Such a refusal can occur for entirely different reasons that require special attention. However, most of these can lead to costly motor repairs. So let’s figure out how to proceed in such situations.

What causes a car to stall in a puddle of water?

A vast number of reasons can cause a sudden stop of the motor in a puddle. If the engine compartment is flooded, then the liquid can penetrate almost all systems. The most common and not very dangerous causes are air filters and spark plugs getting wet. However, the ingress of a large amount of liquid into the engine compartment is always a high risk of water hammer. And then the consequences can be much more severe.

What is a water hammer?

Engine water hammer is one of the most common causes of failure in these situations. Water hammer is recognised as the process that occurs in the piston group – when the volume of the liquid entering the cylinder is greater than the volume of the combustion chamber, the piston reaches the top dead centre. If it is more straightforward, then water gets into the motor and instantly disables it.

The piston’s unexpected and abrupt impact against the water in the cylinder can destroy connecting rods, camshafts, and even the crankshaft. As a result, the damage to the engine can be so severe that even a costly overhaul will not help. One of the signs of an incipient water hammer is precisely the motor coming to a halt, accompanied by an uncharacteristic knock.

How to proceed in such a situation?

Please take all necessary steps to get the vehicle out to a dry place without starting the engine, for example, with the help of a tug or even pushing it out on your own. It is highly advisable to do this as quickly as possible before the water spreads where it is not supposed to be.

After pulling the vehicle out onto a dry area, let it sit for at least 20 minutes. Only after that can you proceed to the inspection to determine how badly the engine has suffered and why the car that has driven into a puddle will not start.

How to check the car:

1. Always start with the air filter. First, you need to remove it and make sure that it does not get wet. If it is dry, one of the problems has disappeared, and you can proceed to the next step.

2. The next step is to check the condition of the spark plugs. If streams of water flow from the holes, you must remove them entirely.

3. Next, it is worth checking the oil level in the engine and box. If white traces are visible on the dipstick or the oil level has risen noticeably, this is the main symptom of a large volume of water entering the oil. For the engine, about half a litre is critical. According to your assessment, if there is more water, it is better to call a tow truck and go to the service.

How to safely pass water obstacles?

There is no universal solution since everything depends a lot on the depth of the puddle. But the main rule is the same for everyone: try to drive evenly in the lowest gear. At the same time, it is essential to keep the engine speed at a minimum stable level.

Any attempts to accelerate or decelerate will be accompanied by the rolling of waves with the risk of flooding the engine compartment. So always keep a spare corresponding tyre or tyres in your trunk. For example, suppose you own a sports car. One suitable fit would be the Dunlop SP Sport LM705.

In addition, it is necessary to select a driving mode so that the car travels with the speed of the wave that is formed in front of it.