Fuel filter for a diesel engine: device, replacement, principle of operation

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

The engine power system includes a lot of important elements, including filtering ones. They are present on both gasoline and diesel engines. As for the latter, such engines are more demanding on fuel quality. Therefore, the diesel engine fuel filter device is slightly different from gasoline counterparts. So, let's look at the design and purpose of these elements.

What is it used for?

Even with the highest quality manufacturing, diesel fuel is subject to various contaminants. And it happens even in the oil refining industry. Further pollution occurs during its transportation and refueling. It is also worth noting that such fuel undergoes oxidation during long-term storage, impurities and turbidity form in it.

Varieties

Diesel fuel filter can be twocleaning types:

• Fine.
• Rough.

On some models, an additional separator is installed. This modular unit includes a diesel fuel filter and water separator. It contributes to the high-quality purification of fuel not only from impurities, dirt and tar, but also from water, which may occur due to condensate.

Separators are not installed on gasoline cars, and a mesh (made of plastic or metal) on a submersible fuel pump can perform a coarse cleaning function. Therefore, the diesel engine fuel filter arrangement is slightly different.

Coarse cleaning

This item includes a body, inside of which there is a reflective mesh. All this is hermetically sealed with a paronite gasket. There is a sludge dump valve at the bottom of the element. It must be opened periodically to prevent premature clogging of the filter.

Passing through the element, the fuel is cleared of large particles of dirt. That is, the principle of operation of the diesel engine fuel filter (coarse cleaning) is to prevent clogging of the fuel even before it enters the system and lines. On some vehicles, the element contains an intake reduction valve. Its purpose is to control the level of working pressure in the fuel system.

Fine cleaning

This element serves for the final filtering of fuel beforeit will enter the pump and spray nozzle. Sometimes the part is installed in the pump itself, but most often it is located in the area of \u200b\u200bthe fuel line. This element is indestructible. Therefore, the replacement of the fuel filter on a diesel engine is carried out entirely, without repair and other restorations. According to its design, it is a glass body, inside of which there is a cleaning element. The latter is made of porous paper. The pore thickness is not more than 10 µm. It is this value that is the maximum for the injectors and the pump. Larger particles will clog the system.

The fuel itself enters the filter through the fittings. According to them, it also comes out, but already in a clean state. Distinguish between inlet and outlet. They can be optionally equipped with a plastic tube with fittings.

Working principle

How does a diesel engine fuel filter work? The principle of its work is as follows. Fuel from the tank passes through pipelines to the coarse filter, where it is cleaned of dirt up to 25 microns in size. Then it enters the inlet hose of the fine cleaning element. In the filter housing, the fuel passes through porous paper, where, being cleaned of small impurities, it passes further along the line. By the way, this paper has the same structure as on the oil filter.

Three-barrels

Some cars are equipped with more complex parts. For example, the fuel filter device of the Opel Astra diesel engine assumes the presence of threefittings. Two of them are the main ones, which serve for the entry and exit of fuel. And an additional third one performs the function of dumping fuel into the tank if the pressure in the system exceeds the allowable values. Domestic vehicles do not have this diesel fuel filter.

Resource

The service life of gasoline cleaning elements is quite high. Car mileage with them is about 90 thousand kilometers. Some manufacturers say that their validity is equal to the life of the entire engine. Of course, this can only be achieved with ideal fuel quality. As far as our history goes, Bosch diesel fuel filters last between 15,000 and 30,000 kilometers.

Reviews of motorists say that this is a very good filter model and it does not cause problems with use. Why such a run-up in terms of replacement? This resource depends on the quality of the fuel. Fuel at gas stations has a different level of contamination, hence such values. The presence of large particles in the element reduces its throughput. How do you know when it's time to change diesel fuel filters? Reviews of experienced motorists note a decrease in traction, the dynamics of car acceleration. Sometimes the car moves jerkily, the motor reacts with a delay to the gas pedal. Floating idle speed, increased consumption - all this is the cause of blockage.

Replacement

Before changing the fuel filter on a dieselengine, you need to find its location. Often it is located in the engine compartment - in front of the fuel rail. Sometimes, to get to it, you need to remove the plastic engine cover. You can see it immediately by its characteristic size and shape (pictured below).

This is the diesel fuel filter. "Volkswagen Passat TDI" is equipped with them as well. On some vehicles, it is located under the bottom. You can immediately see it by the thick fuel lines coming up to it.

Next, prepare a container for draining, as a small amount of fuel will spill when dismantling the fittings. You can go the other way - to make the system work on the remaining fuel, and so that it is in the tank, but not in the right place for us. It is very simple to do this - you need to pull the fuse to the pump and start the car, letting it run on a small part of the fuel that was left after it. The fuse box is located to the left of the steering column. There is a pinout on the back cover. If this is a foreign car, pull out the fuse responsible for the Fuel Pump. Replacing the fuel filter for a diesel engine is quite simple. To do this, you need a minus screwdriver or a wrench (most often “12”). Remove the inlet and outlet fittings, and also unscrew the filter mounting bolts. We install the new element in place. Some motorists buy filters for dieselheated engines. This is a very useful feature that prevents fuel from freezing and paraffin buildup on the paper walls. When installing a new element, it is important to observe the direction of filtration. It is indicated by a special arrow.

Its beginning is the inlet fitting. An outlet tube is installed at the end, from which clean fuel will flow into the nozzles. Do not confuse the arrow, otherwise the system will be clogged. After installation, carefully check the reliability of all connections. The tubes should not be fierce, and the filter itself should not hang out on the mounts.

Requirements

A quality element provides not only reliable protection against dirt, but also against moisture. It can accumulate on the walls of a half-empty tank when the car is parked overnight. Poor quality filters do not protect the system from condensate ingress, which is why moisture gets into the rail with the fuel, and then into the combustion chamber. As a result, the inside of the line rusts, and the engine compression drops due to an improperly prepared mixture.

One more requirement - the filter must work efficiently even at low temperatures. The cold causes the fuel to crystallize, causing it to turn into paraffin. To prevent this from happening, the filter is equipped with a heating system. The sensor monitors the temperature in the tank and ensures the optimum mixture when starting the engine. If you live in northern latitudes, be sure to set a filter withheated. In its absence, thick fuel quickly clogs the cleaning element, and sometimes even gets into the injection system, due to which the engine loses power and does not start.

Replacement when disassembling the case

If you need to disassemble the old filter housing (cartridge) to install the element, be sure to clean it. During operation, sediment forms on its walls, which can be dumped through the lower drain valve. But if one is missing, you will need a rune vacuum pump. It sounds like something complex and technologically advanced, but an ordinary medical syringe can serve as such. By pulling its handle up, you will take in all the sediment that has accumulated inside. It is not only dirt, but also water. Further, if the walls are also dirty, wipe them with a dry, fluffy rag. Before installing a new filter, the cartridge must be perfectly clean. Check the condition of the sealing ring. If it is stretched or shows signs of wear, replace it with a new one. Next, close the lid, connect all the hoses and turn on the ignition for a few seconds. The fuel pump will begin pumping diesel into the cartridge. Then you can safely start the engine.

So, we found out the device and principle of operation of the fuel filter for a diesel engine, and also learned how to change it ourselves.