Engine shock and its consequences
Experienced motorists are aware of the negative factors associated with driving on wet surfaces. After a heavy rain, pits and hollows in which water is collected are especially dangerous. Such coating defects should be avoided not only because of mechanical damage to the car body, but also because of the risk of engine hydraulic shock, as a result of which water penetrates into the combustion chamber. In the future, there may be several scenarios for the development of the problem, based on which the optimal recovery option for the power unit is selected.
How does a water hammer
Although the effects of a water hammer can cause serious damage, appropriate conditions must be created to obtain it. Of course, this happens by chance, so the water hammer still belongs to rare phenomena. In order for it to take place, water must penetrate into the cylinders in a volume exceeding the reserve of the combustion chamber when the piston reaches the upper compression point.In other words, the engine shock is a critical hit of fluid in the cylinders. The occurrence of damage due to the fact that the pistons just can not compress the water. As a result, the engine mechanisms involved in the work of the cylinders are broken. In this case, there may be several variants of malfunctions, both with a minimum degree of severity and involving the need to replace several elements of the system at once.
Options for damage from water hammer
The most common are two scenarios in which the consequences of a water hammer develop. If, after driving through puddles, the engine stops working, this does not necessarily indicate a fatal problem that may arise in such a situation. Most likely, there was a deformation of the rods. Further actions of the car owner can be as follows: call a tow truck and replace the connecting rod-piston system in the nearest service center. Oddly enough, the most serious consequences of the hydraulic shock of the engine can be suspected if the car continues to drive. All breakdowns will show up in the future and their scale can be impressive. In any case, the connecting rod will be damaged and will signal it with small knocks arising due to a violation of symmetry between the axes of the holes in the heads of the mechanism.To understand the nature of the described failures should consider in more detail each of the above scenarios.
Deformation of rods
As a result of the contact of the piston with water, the crank exerts a tremendous force of compression, provided not even by the engine, but by the inertia of the machine that continues to drive. Through a transmission with wheels, the crankshaft rotates, bypassing the piston resistance at the compression stroke - this leads to a breakdown of the connecting rod. Between the connecting rod and the piston creates a huge effort that does not allow the latter to perform a twist on the finger. At the same time, the piston should spin in the cylinder with the connecting rod. Thus, on one side of the piston skirt there is a load that deforms the element. In this case, the hydraulic shock of the engine may not necessarily lead to complete failure of the part. Damage can be expressed by a slight deformation, but if the micrometer detects a violation of the geometry of the element, it is necessary to replace it.
Consequences of the connecting rod strain
How the engine will respond to the resulting defects is difficult to predict. Much depends on the characteristics of the cylinder system itself, but usually two types of events are distinguished:
- If the deformation has an impressive size, the crank can rest against the bottom of the cylinder, after which the power unit stalls.
- At insignificant deformation, which does not exceed 3 mm, the piston will stop at the lowest point and will lock onto the crankshaft counterweights. The subsequent half-turn and contact with the "cheeks" will entail its destruction - again, the severity may be different.
If the car went further, it means that the piston system managed to bring water to the next half-turn. In general, it can be concluded that the engine after a water hammer with a slight ingress of fluid is more likely to get serious damage, since the continuation of its operation affects not only the connecting rods, but also other elements of the system. If the driver did not hear the sounds of the connecting rod, in the process of movement there will be additional loads. In this case, the following malfunctions are not excluded: a damaged cylinder, a broken rod, a broken piston, a broken block, etc.
A common problem in such cases is damage to the air filter. But much depends on the material from which it is made.The most dangerous engine water shock is for paper filters. Even if it is preserved in its wetted form, then after drying, serious deformations are not excluded. But this mainly concerns outdated models, since the new filters still use more technologically advanced synthetic materials that are resistant both to mechanical stress and to the aqueous medium.
Diagnostics of water hammer
Driving deep puddles, you should prepare for the fact that a water hammer was obtained. Especially if already in the cabin there is an uncharacteristic operation of the engine. However, even if the car stalled, it does not always indicate the penetration of fluid into the engine - this, for example, may be a violation of the electrical wiring, which is also sensitive to water. Anyway, in order to facilitate the repair of the engine after a hydraulic shock, it is necessary to fix the fact of its completion as soon as possible. If there is the slightest doubt, it is better to immediately open the air filter and check its condition. The presence of moisture will be a disappointing diagnosis. Further it is necessary to check the cylinders. To do this, unscrew the spark plug and try to start the starter. If there is water in the cylinders, the engine will spray it out.But there may be another starter reaction - for example, if it does not move, the water hammer may have already damaged the working mechanisms. In this case, you can not start the car with a jolt.
Diesel engine hydraulic shock
There are different opinions regarding the impact of hydraulic shock on diesel. First you need to figure out how this engine differs from the gasoline one. Diesel units do not have the ability to choke air, and the combustion chamber is of a smaller volume. Since the compression is high enough, it becomes impossible to compress the water, which is why there are no less serious consequences. In particular, the same breakdowns of the connecting rod are possible, but with greater force.
There are many supporters of another point of view - that the diesel engine hydraulic shock is not capable of causing damage to its working elements, since water evaporates during compression under high temperature. That is, the liquid penetrating into the cylinder naturally expands and turns into vapor. In this case, much depends on the volume of water, since the process of its expansion can cause negative effects even before evaporation occurs.
Engine recovery after hydraulic shock
Much of the repair measures after a water hammer is determined by the severity of the damage. In any case, the sooner they are discovered, the better. Usually requires a full revision of the connecting rod-piston elements, which covered the hydraulic shock of the engine. Repairs may include the replacement of one or more cylinders. The consequences can also appear in a month in the form of the formation of traces of corrosion on piston parts and the same cylinders. To eliminate rust, it may be necessary to bore cylinder cups and further polish the affected surfaces. Bent rods, as a rule, do not imply recovery, so they should be replaced immediately. However, minor defects on the cylinder head can be repaired, but only in specialized car services on the appropriate equipment.
How to avoid water hammer
To minimize the risk of water hammer can only be under the condition of careful driving in "wet" weather. The presence of deep puddles on the roads should be a reason for driving at low speed. To understand how to avoid the hydraulic shock of the engine of a particular car, it is necessary to consider the level at which the air intake is located.Depending on its characteristics and hermeticity, it is possible to imagine approximate risks of getting a water hammer during overcoming a puddle. For some models, a small pit is sufficient, while others will not be affected by the abundant wave of rainwater. Do not forget that the water hammer causes not only poor coverage on the road, but also defects in the gasket on the cylinder block. If there is a leak in it, then coolant may well get into the cylinders when the car is standing.