Diagnosis of faults and replacement of the oil pump on a VAZ 2108/2109

Where is the oil pump located on the VAZ 2108/2109, what is it responsible for

The oil pump in the engine design of every car is an important and integral mechanism, which is designed to create a certain pressure in the engine lubrication system. The design of the unit comes in various forms and can be driven by a camshaft or crankshaft.

On such common models as the VAZ 2108/2109, the device for circulating oil in the system is located behind the crankshaft pulley. Looking under the hood, you won’t be able to examine it so easily: this can only be done after removing the crankshaft pulley from the engine.

The pump is fastened to the cylinder block using six bolted connections, which ensures reliable fixation of the entire structure.

The oil pump on the VAZ 2108/2109 is located behind the crankshaft pulley, so it is not so easy to examine this element

How to remove the timing belt?

Approximately every 60 thousand kilometers, the timing belt on VAZ 2108-21099 vehicles needs to be replaced. The pump is dismantled every 90 thousand, but it is better to change everything at once. Of course, you can travel more if you carry a spare set in the trunk. But is it worth carrying out repairs in the field if you can do it in the garage, without haste and the risk of bending the valves?

After all, not all engines are protected from the impacts that valves receive when the timing belt breaks. The whole point is that, after accelerating the car, you keep the engine speed high. When the belt breaks suddenly, the camshaft is set to a position in which all the valves fall down, that is, they open. But the crankshaft continues to rotate by inertia, moving the pistons.

And he moves them towards the lowered valves. The result is a severe blow, which at best will lead to bending of the valves. It may also happen that the piston bursts and cracks appear along the cylinder head. Because of this, repairs immediately become several times more expensive. To replace the timing belt on a VAZ 2108, you will need to prepare the car.

First of all, install it on a flat surface so that it can be easily approached from all sides. The right wheel will need to be removed and a good and reliable support placed under the car. It will not be difficult for you to get rid of the casing that covers the compartment with the gas distribution mechanism. It is secured with three bolts to the engine block. Underneath you will find a belt running along the crankshaft pulleys, pump pulley, camshaft pulley and tension pulley.

To dismantle the belt, you will need to unscrew the roller fastening nut with a 17 wrench. Using the same wrench, unscrew the generator mounting nut. Move it towards the engine, thereby weakening the generator drive. Next, unscrew the bolts securing the protection to the car body, remove the drive pulley for the VAZ 2108 generator belt. The rubber timing belt is easily removed from all pulleys and the tension roller.

Symptoms of a faulty oil pump

The first thing that will indicate problems with the oil pump is the oil pressure light coming on. In this case, the element indicates that there is a problem with the engine lubrication system. How serious they are remains to be determined by the car owner. In addition to checking the pressure, attention should be paid to oil consumption. If the pressure in the lubrication system of the power unit decreases, the vehicle should not be operated until the cause is determined and repairs are made. The main symptoms of problems in the system are a light coming on or a knocking sound in the engine.

Actions to be taken in the event of a breakdown:

• stop and turn off the engine;
• wait a while for the oil to drain into the engine crankcase, then check its level using a dipstick. If the level is minimal, you need to top it up to normal;
• start the engine;
• If the oil pressure lamp continues to light and extraneous noise is still heard from the engine, this may indicate a possible problem with the oil pump.

One of the reasons why the oil pressure light comes on may be a low level of lubricant in the engine.

How to check the oil pump

To test the mechanism, it is not necessary to dismantle it. For diagnostic purposes, it is necessary to measure the pressure in the lubrication system and compare it with the readings that correspond to the norm for a particular car. Based on the results obtained, we can draw conclusions: is there any cause for concern or not. If it is necessary to replace the oil pump on a VAZ 2108/2109, it is recommended to use only original parts. This is explained by the fact that many people today produce components for cars in the domestic automobile industry. However, their quality leaves much to be desired.

When replacing the oil pump, it is recommended to purchase an original part to avoid problems due to poor workmanship

Checking the oil pump on the stand

If possible, you can check the performance of the oil pump on a special stand. The essence of such a test is to evaluate the performance and pressure generated by the device, as well as the pressure at which the pressure relief valve operates. When testing the pump using a stand, special oil with a temperature of +20 ˚С is used. For an oil pump for a VAZ 2108/2109 engine, the flow rate should be within 34 l/min, the back pressure should be 5 kg/cm². The pressure relief valve should open at a pressure of 5.5–7.5 kg/cm². If the valve is checked on the engine using a pressure gauge, which is installed instead of an oil pressure sensor, the valve must operate at a pressure of at least 4.5 kg/cm².

What pressure should be in the system?

The sensor serves only to determine the pressure drop, but it does not indicate the exact indicator of this parameter. Therefore, a conventional 10 bar dial pressure gauge is used for measurement.

For measurements, you can use any device, adapting it to the engine or using a pressure gauge specially designed for this.

To use a conventional pressure gauge, you will have to improve it a little so that it can be connected to the motor. To do this, you will need the pressure gauge itself, a piece of thick-walled rubber tube, clamps and a threaded fitting for the hole for installing the pressure sensor.

We connect all this into one structure, and securely clamp the joints of the tube with the pressure gauge and fitting with clamps.

With a special pressure gauge for measuring oil pressure on engines, such a procedure is not required, since it is already equipped with a fitting and adapters for connecting to the engine.

Measurement is performed using the following technology:

• Disconnect the wire and unscrew the pressure sensor;
• We screw the pressure gauge into the sensor seat and tighten it well (but do not overdo it, since the thread in the hole is aluminum and breaks easily);
• We briefly start the engine (a short period of engine operation will not cause any damage);
• We look at the device readings.

If the pressure gauge shows pressure above 1 Bar, the lubrication system is functioning normally and the cause should be sought in the sensor or wiring.

Causes of malfunction of VAZ 2108/2109 oil pumps

Before deciding to repair or replace the oil pump, it is worth understanding the reasons that may indicate problems. By the way, problems are possible not only with the mechanism itself, but also with other elements of the lubrication system:

• decrease in pressure in the crankcase;
• problems with pressure sensors;
• use of low quality motor oil;
• using oil that is not suitable for this vehicle;
• problems with the lubrication or safety valve;
• oil filter clogged;
• contamination of the oil receiver or pump housing.

Contamination of the oil receiver leads to a decrease in pressure in the system and the light comes on.

The blockage may occur due to contamination of the engine crankcase itself. The problem is solved by removing and cleaning the pan. The operation of the oil pump can be disrupted by other problems that are identified during the diagnostic process. These include:

• gasket damage;
• unreliable filter fastening;
• high wear of mechanism parts;
• reduction valve failure.

The oil pump is a fairly reliable component with a long service life. Breakdowns usually occur due to improper repairs or poor quality lubricants.

Checking the oil receiver

Oil pump VAZ 2109

As a rule, the oil receiver tube is equipped with a screen, at the end of which there is a mesh to prevent the penetration of large debris. Through this element, oil is sucked into the pump from the crankcase. Pump wear can occur due to carbon, contaminants, or other microscopic particles. To check the oil pickup you need:

• remove the oil pan from the engine;
• The element is replaced when it becomes clogged or broken;
• It is quite difficult to clean the oil receiver, since small debris may not be noticed.

Disassembly and repair

After completing the dismantling work, you can proceed in two ways:

• Replace the old pump with a new one;
• Repair the old oil pump.

Repair allows you to identify worn elements and replace them with new ones, which will restore functionality. If the breakdown is more serious than simple wear and tear of consumables, the optimal solution would be to completely replace the oil pump.

To disassemble the pump, follow the instructions.

• Divide the pump into two parts. To do this, we have already unscrewed 6 bolts securing the cover to the body and used a screwdriver to pry off this cover. It came out of the pins on the body. So we remove the element and put it aside.
• Inside the pump housing there are driven and drive gears, which need to be removed and placed aside for now. Then we will check their condition.
• Next, the pressure reducing valve is removed. To do this, first unscrew the valve plug and remove the spring from the hole, and then the valve.
• In some cases, problems may arise with removing the valve. If you encounter this situation, gently tap the oil pump body against a piece of wood or use a wooden cone-shaped pin. It is inserted into the valve hole, the valve is hooked and removed.
• After disassembling your oil pump on the VAZ 2109, thoroughly wash all its components using clean kerosene. Don't forget to wipe the parts dry afterwards.
• Check the condition of the cover and body of your pump for mechanical defects, chips, cracks.
• Pay special attention to the landing spots of the gears, where there should be no signs of wear or other mechanical defects. If they are, the pump will have to be replaced.

In many ways, the performance and maintainability of the old oil pump depends on the results of checking the characteristics of the cover and body of the device. It is necessary to take measurements of the gaps.

Check location

Requirements

Driven gear seat diameter

The diameter may increase as the pump operates and friction occurs. The normal diameter of this place for the VAZ 2109 is 75.1 millimeters. If there is a deviation in the direction of increasing diameter, the pump must be replaced.

Thickness of the mating wall

Under normal conditions, this parameter is 3.4 millimeters. If the gap is less than specified, the pump is replaced completely

Drive gear thickness

The normal value is 7.42 millimeters. When the size is reduced, the pump goes to a landfill, and a new one is installed in its place.

Driven gear thickness

For her, the normal parameter is a thickness of 7.35 millimeters. As with the drive gear, deviation from the norm means replacement

Drive gear axial clearance

To measure, take a metal ruler and feelers of 0.12 and 0.15 millimeters. The gap is checked as follows: a gear is placed in the pump housing and a ruler is placed on top with its end. The gap between the end of the ruler and the plane of the feeler gauge is measured. For the drive gear, the gap is 0.12 millimeters

Device

The device in question may schematically look like this:

Main elements of the oil pressure sensor:

• frame;
• wire connection location;
• thread for fixation in the cylinder block;
• diaphragm;
• a spring that resists deformation of the diaphragm;
• positive and negative contacts.

The oil pressure sensor is located on the left side on the back of the engine. This makes it fairly easy to diagnose or replace.

Cold engine measurements

In order to measure the pressure, before starting the engine, you need to make sure that the oil temperature is equal to the ambient temperature. The emergency sensor in the VAZ is configured to trigger at a pressure of 0.33 kgf per square centimeter. If the measurement result turns out to be like this, then it is necessary to dismantle the pump and troubleshoot it. With a gradual increase in the crankshaft speed, the pressure should increase to 4.5 kgf per square centimeter. The pressure relief valve should work, so the pressure will not increase further.