During engine operation, not only exhaust gases are released. Few people know about crankcases. At the bottom of the engine, fuel, oil and water fumes accumulate. Their accumulation worsens and destabilizes the operation of the motor. To remove these substances, the crankcase ventilation valve is provided in the vehicle design. Tuareg is also equipped with it. What is this element and how is it arranged? You will read the answers to these and many other questions in our article today.
Characteristic
Note that the crankcase ventilation system has been used for a very long time. The essence of her work is very simple - the inside of the engine is connected to the exhaust manifold using a hose. Under the influence of the rarefaction force, water and oil vapor accumulated in the engine are taken back into the intake tract.
On BMW cars, the crankcase ventilation valve is designed so that the gases move in only one direction.
Types
There are two types of data systems:
The first type was used on older engines. Here, ventilation was carried out in the cover of the pushers through an outlet pipe. All gases went out into the engine compartment. The system was ineffective, so in the late 70s, automobile manufacturers began to use a closed crankcase ventilation valve. Opel was no exception. The advantages of such a system were as follows:
- The level of emission of substances into the atmosphere decreased.
- The engine did not experience “starvation” and worked stably at any speed, giving the necessary traction.
- The pressure inside the crankcase decreased. This contributed to a greater resource of gaskets and gaskets (they simply squeezed them out in an open system).
Valves are also distinguished by the type of exhaust gas in the intake manifold. There is a direct-flow valve for crankcase ventilation and forced type. On Volga cars with ZMZ-402 engines, gasoline and oil vapors were removed through a thick pipe. He connected the valve cover to the carburetor. As a result, the gases entered directly into the intake manifold, without affecting the mixing of a portion of the fuel-air mixture.
Device
Now cars use a membrane-type crankcase ventilation valve. It consists of the following elements:
- Lids.
- Aperture
- Return spring.
- Housings.
The latter has 2 fittings. One is designed to supply crankcase gases, the second - for their removal.
How does it work?
The effect of the mechanism depends on the operating mode of the engine. So, on a drowned motor, the valve is blocked by a diaphragm under the force of a return spring.
When the unit is idling, the membrane overcomes the force of the spring (since vacuum is generated in the system), and some of the gases enter the intake manifold. Then they, along with the fuel-air mixture, are burned in the chamber and are discharged into the atmosphere. At speeds of more than one and a half thousand, the channel is completely freed by the diaphragm. So, crankcase gases enter the inlet in full. Thanks to the membrane, they will not be able to get back into the crankcase.
How to check
During operation, the crankcase ventilation valve begins to clog. However, this does not mean that the element has stopped working and needs to be replaced. To check whether the crankcase ventilation valve is serviceable, its nozzle is disconnected from the engine and blown to one side. On a working mechanism, the air in the opposite direction should fall in a small volume.
There is another way to check the crankcase ventilation valve. To do this, start the engine and disconnect the pipe from the intake side, after loosening the clamp on it. Next, apply a thumb to the fitting. With a functioning valve, it must be suctioned. This suggests that there is a vacuum in the system.
Some diagnose the very condition of the engine through this valve. So, between the hose and the intake manifold a transparent fuel filter crashes (this is installed on carburetor engines). After some time, oil and soot will appear on it. If the filter becomes dirty during the first 100-150 kilometers, it means that the cylinder-piston group is faulty in the engine. Although the system is designed to circulate harmful substances, so much dirt should not go through the valve in such a short period of time.
Possible malfunctions
If there is no negative pressure in the system and gases do not enter the intake manifold, the reason is one of two things:
- The crankcase ventilation valve is out of order.
- Clogged system hoses.
In the latter case, the main cause of the problem is the wear of the piston group. It is worth checking the compression in the cylinders. Also check oil scraper rings. If they are weakened or “laid down”, oil will enter the system in large quantities. Hose will coke. Along with this, the valve membrane itself is broken. Why is this phenomenon dangerous? If the system cannot normally pump gases, they will accumulate in other places, and under high pressure. So, they squeeze out oil seals and gaskets. Traction disappears in the motor; it is unstable at idle.
If the compression is normal, and the hoses do not have blockages, the valve itself is to blame. In such a situation, it is enough to simply replace it with a new one.
Price
How much does the crankcase ventilation valve cost? BMW is equipped with a device for 2-2.5 thousand rubles. For a Ford Focus car, this element costs up to one and a half thousand rubles. On domestic VAZs, the valve costs no more than a thousand.
How to replace with your own hands?
Let's look at how to change this element yourself, using the BMW M-54 engine as an example. So, first you need to find the crankcase ventilation valve itself. It is located in front of the engine, under the intake manifold. Having reached it, we remove the idle speed control and the electronic throttle. For convenience, the intake manifold itself can also be dismantled (but not necessary).
Now disconnect the hoses from the ventilation valve and remove the element itself out. Installing a new device is performed in the reverse order. For reliability, all hoses are secured with clamps.
Conclusion
So, we found out how the crankcase ventilation valve is arranged and works. When operating a vehicle, periodically check the condition of this unit. After all, if the valve is clogged, you can "get" to replace the seals and gaskets. And this is an additional cost of both money and time. Also note that if there is a blockage in the hoses, the matter is not limited to one cleaning. If there are problems with the piston, this carbon deposits form in a couple of days. Riding with such a malfunction is not recommended. Indeed, the pressure in the crankcase is many times higher than normal. It is necessary to check the compression of the engine and, if possible, the condition of the oil scraper rings.