The crankcase ventilation system ensures the removal of crankcase gases.

Crankcase gases flow through the exhaust hose to the oil separator located on the cylinder block

Cleaning the crankcase ventilation system VAZ-2123

The hoses of the first and second circuits are two hoses (one small diameter, the other large), through which the crankcase gases that have passed the oil separator are fed into the receiver and then into the combustion chamber.

The first circuit has a calibrated hole - a jet with a diameter of 1.7 mm.

The jet is located in the hose of the first circuit (small diameter hose) on the side connected to the oil separator fitting. The hose of the first circuit goes from the oil separator to the receiver.

The second circuit hose (larger diameter hose) goes from the oil separator to the intake pipe hose.

At idle, all crankcase gases are fed through the primary circuit nozzle (small diameter hose).

In this mode, a high vacuum is created in the intake pipe, and the crankcase gases are effectively sucked into the throttle space.

The jet restricts the volume of exhaust gases, so that the engine operation at idle is not disrupted.

Under load conditions, when the throttle valve is partially or completely open, a small amount of crankcase gases passes through the primary circuit jet.

In this case, their main volume passes through the second circuit (large diameter hose) into the intake pipe hose in front of the throttle nozzle and is then burned in the combustion chamber.

In the absence of a 1.7 mm jet, the ECM mistakenly determines an overestimated value of overflows through the throttle valve (the nominal value determined by the manufacturer is 3 - 5 kg / hour), which leads to instability of idle speed.

Cleaning of the crankcase ventilation system

Over time, resinous deposits from crankcase gases accumulate in the engine crankcase ventilation system, making it difficult to remove these gases into the engine cylinders for combustion. Because of this, the gas pressure inside the engine increases, and oil leaks appear through the seals. To avoid this, periodically clean and flush the system.

Clean the crankcase ventilation system before each oil change.

You will need: a screwdriver, a key "for 13", kerosene for washing, clean rags, a container for washing parts.

The nut of the oil separator attachment is difficult to access without a special tubular key. If there is no such key, clean the oil separator without removing it from the engine.

If a large amount of kerosene gets into the engine crankcase when cleaning the oil separator, replace the oil in the crankcase.

We remove the tips of high-voltage wires from the spark plugs

Remove the oil level dipstick from the guide tube

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

Unscrew the oil supply tube fitting from the cylinder block hole to the hydraulic chain tensioner timing drive and unscrew the two bolts securing the tube holders

With a screwdriver, loosen the hose clamp of the main crankcase ventilation circuit

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

We remove the hose from the nozzle of the oil separator cover

Using pliers, we loosen the hose clamp of the crankcase ventilation idling circuit

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

And remove the hose from the nozzle of the guide tube of the probe

With a cap wrench for 13, unscrew the cap nut for fixing the oil separator lid

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

Remove the copper sealing washer

Remove the oil separator cover, removing it between the oil supply tube to the hydraulic tensioner and the cylinder block wall

The connection of the lid and cylinder block is sealed with a paronite gasket

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

Screw two M8 nuts on the oil separator stud

We close the nuts with two keys on 13

Unscrew the stud for the lower nut with a key for 13

Cleaning the crankcase ventilation system VAZ-2123Cleaning the crankcase ventilation system VAZ-2123

Removing the hairpin from the oil separator

We grab the edge of the oil separator with pliers

Cleaning the crankcase ventilation system VAZ-2123

Remove the oil separator from the cylinder block socket

We wash the oil separator parts with gasoline or kerosene and install them in reverse order.

We also wash the hoses of the ventilation circuits