Water hammer - This is a common phenomenon in which water enters a running car engine, disrupting its operation.

If a car drives at a high speed in a puddle or moves during heavy rain, there is a risk that moisture will be in the air filter, which is why the engine will stall, since the presence of water in the combustion chamber makes ignition of the fuel mixture impossible. The engine can stop regardless of the speed and speed, and the consequences of a hydraulic shock are very significant.

Dangerous breakdowns

If a large amount of water gets inside, the engine stalls with a characteristic jerk, and the connecting rods are damaged as a result of damage: they are deformed due to mechanical impact. The connecting rod and piston group is to be replaced as an assembly; for it, the car will have to be evacuated and delivered to a car-care center. Damage to the mechanisms due to the fact that in a collision of water and a piston on the connecting rod, a powerful compression force arises from the inertia of a moving car. The degree of deformation results:

• the connecting rod rests against the wall of the cylinder, causing the motor to jam;

• slight deformations lead to a change in the position of the piston and its subsequent destruction during operation;

When a small amount of water gets in, the motor may not stall, since the mechanism squeezes out moisture at high speeds, however the crank gets microscopic deformation. Such deformations are indicated by a characteristic knock arising during movement: it appears when the position of the axes changes in the connecting rod heads, which are no longer parallel to each other, but with displacement. Such a situation is more dangerous, since it is more difficult to determine a malfunction without diagnostics in the service, and the consequences are more severe:

See also: Replacing the timing belt on the Audi A4 2.0 TDI 2007 onwards.

• breakage of the connecting rod;

• deformation of pistons and cylinder;

• breaking the cylinder head;

• damage to the engine elements as a result of metal fatigue (usually they make themselves felt after 4-6 thousand kilometers after a breakdown).

If the car is equipped with a diesel engine, then after the occurrence of a water hammer, it will not go further. The reason is that diesel engines have small combustion chambers and they do not have a throttle valve. Cranks of a diesel engine break instantly, and even after a weak hydraulic shock, it will have to be driven to service.

How to avoid water hammer

Repair of the engine after hydraulic shock is quite expensive regardless of the make and model of the car. Therefore, to avoid water hammer, observe the following rules:

• do not drive without need through deep puddles (fords).

• it is undesirable to drive in heavy rain;

• after a trip during a rainstorm, it is worth visiting a car-care center and diagnosing the connecting rod-piston group to check whether the parts did not receive damage.

 Particular care should be taken when driving through puddles and in heavy rain to drivers of cars with a diesel engine and a low-lying air intake: such cars are more sensitive to water ingress.