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Chevrolet Lacetti. Diagnostics of malfunctions of the engine crank mechanism

The performance of the crank mechanism can be assessed by measuring oil pressure, determining the characteristics of knocks and measuring gaps in certain joints crankshaft.

Oil pressure measurement

Oil pressure is checked using a device consisting of a pressure gauge, a connecting hose with a union nut and nipple, and a damper that smoothes out oil pulsation during pressure measurement. To take pressure readings in the main line, the device is connected to the housing oil filter, having previously disconnected it from the standard pressure gauge tube. To check the pressure, follow the following steps in sequence:
connect to the oil filter housing measuring device;
start and warm up the engine to standard thermal condition;
record the oil pressure in the main line at idling, at the moment of stable and nominally high-speed rotation of the crankshaft.

Listening for knocking noises in the crankshaft joints

Knocks in the KShM are listened to in certain conjunctions using an electronic autostethoscope. This method of diagnosing CVM requires injection of rarefied pressure into the space above the piston using a special compressor-vacuum installation. It is necessary to listen to the connections between the piston pin and the piston boss, also between connecting rod mechanism and the crankshaft journal, and then between the connecting rod upper end bushing and the piston pin.

In the case where low oil pressure and knocking noises in the crankshaft are detected, you will need to check the gaps in the above connections and replace the oil pressure sensor. If the oil pressure is low, but there are no knocks, then the drain valve of the lubrication system should be adjusted. If the actions taken do not lead to normalization of the pressure, then a diagnostic check of the lubrication system will be required at the stand.

Diagnostics of the crankshaft drive by the width of the gaps in its mates

The condition of the crank mechanism is also determined by the size of the gaps in its connections. They are measured using a special device and according to the following scheme:
install the cylinder piston in a compressed state;
lock the crankshaft;
instead of an injector, fix the device in the cylinder head, loosen the locking screw, and then lift the guide up;
turn on the device and bring the pressure to a discharged state;
achieve stable indicator readings using the method of two or three feed cycles;
record the gap in the connection between the upper head of the connecting rod and the piston pin, and then the total gap between the connecting rod bearing and the upper head of the connecting rod.
All clearances in the crankshaft are measured three times and take the arithmetic average. If the clearances of any one connecting rod are greater than the permissible values, engine repair is required.

Malfunctions of the crank mechanism include decreased compression in the cylinders and engine power, increased fuel and oil consumption, smoking, knocks and noises uncharacteristic of engine operation, oil and coolant leaks.

Compression in the cylinder is measured on a warm engine using a compression meter.

Before measuring compression, unscrew the spark plugs, insert the rubber tip of the device into the hole for the spark plug and turn the crankshaft with the starter with the throttle and air valves fully open for 5-6 seconds. With a compression meter, the maximum pressure at the end of the compression stroke in the cylinder is measured on a pressure gauge scale, while with a compressograph, the pressure value is recorded on a paper form. The measurements are repeated 2-3 times in each cylinder and the average value is determined. The pressure difference in the cylinders should not exceed 0.1 MPa.

A decrease in compression in individual cylinders can occur due to coking or breakage of the piston rings, damage to the cylinder head gasket, or violation of the clearance adjustment valve mechanism or burnt valves. Coking of the piston rings in the piston grooves promotes intensive breakthrough of gases into the crankcase, which can lead to an increase in the pressure of crankcase gases and oil splashing out through the hole for the oil dipstick. In this case, 20-25 cm3 of engine oil is poured into each cylinder and the compression measurements are repeated. An increase in pressure indicates leaks in the cylinder-piston group.

A malfunction of the head gasket and a leak in the valve mechanism can be detected using a pneumatic tester, passing into the cylinder compressed air through the spark plug hole. Air leaking into an adjacent cylinder indicates a damaged head gasket or loose cylinder head nuts or bolts. A faulty cylinder head gasket can also be detected by coolant leaking into the sump. In this case, there will be a constant decrease in the coolant level in expansion tank

or radiator and at the same time increasing the oil level in the sump. The oil acquires a color from gray to milky white. Air leakage through the carburetor indicates a malfunction of the intake valve, and air leakage through the muffler indicates a malfunction of the exhaust valve. Detected faults are eliminated. The reason for the decrease in compression in the engine cylinders when the head gasket and valves are in good condition is wear of the cylinder-piston group. The degree of wear of the cylinder-piston group, and therefore its technical condition , determined without disassembling the engine using instruments and a pneumatic tester. The operating principle of the devices is based on measuring the leakage of air supplied to the engine cylinder. The check is performed on a warm engine. Remove the spark plugs and set the piston of the first cylinder to the top dead center of the end of the compression stroke. The crankshaft is prevented from turning by engaging the gear and placing the car in parking brake

. Press the test tip of the device against the spark plug hole of the first cylinder, open the air supply valve and, according to the indications of the pressure gauge arrow on the device, determine the air leak.

By turning the crankshaft, check the other cylinders in the same way in accordance with the order of their operation. Air leakage should not exceed 28% if the valves and head gasket are in good condition. If knocks and noises uncharacteristic of engine operation occur, listen to the engine with a membrane or electronic stethoscope. The stethoscope rod is installed perpendicular to the surface of the engine in the place where knocks and noises are heard.- a slight clicking knock is heard in the piston groove in the bottom dead center area at average crankshaft speed. Worn pistons produce a clicking, rattling, muffled sound when the engine is cold, which decreases as it warms up.

Wear of the main bearings and an increase in the gap between the crankshaft journals and the liners is accompanied by a dull, low-pitched metallic sound with a frequency that increases with increasing crankshaft rotation speed. A knock is heard in the lower part of the cylinder block along the axis of the crankshaft when the throttle valve is opened sharply.

This knocking noise can also be caused by ignition being too early.

Large axial clearance of the crankshaft contributes to the appearance of a knock of a sharper tone with uneven intervals, especially noticeable with a gradual increase and decrease in the crankshaft rotation speed. The tone of this sound changes depending on whether the clutch pedal is depressed or not. The amount of axial clearance is determined with the engine not running by the movement of the front end of the crankshaft when the clutch pedal is pressed and released and compared with the data from the table.

When connecting rod bearings wear out, they also create a knock in the area of ​​the crankshaft axis, but lower or higher by the amount of the crank radius and when the piston is positioned at the top or bottom dead centers. In this case, a sharper and louder knock is heard, less powerful in relation to the knock of the main bearings. The knocking noise disappears in each of the cylinders when the corresponding spark plug is turned off.

A sign of wear on the main and connecting rod bearings is also a drop in oil pressure in the engine lubrication system below normal. The oil pressure is checked with a control pressure gauge with a division value of no more than 0.05 MPa. Engines with the listed faults are sent for repair. Chevrolet Lacetti is one of the most popular cars among Russian drivers. And this is not surprising. The car is comfortable, reliable and inexpensive. It is a representative of the compact class. Created by the South Korean automaker GM Daewoo. The Chevrolet Lacetti is available in several body styles - sedan,

five-door hatchback

and station wagon. Today, only the first one continues to be released.			What refueling volumes and brands of fuel and lubricants should be filled into the Chevrolet Lacetti	Filling/lubrication point
Filling volume, liters			60	Name of oil/liquid
Fuel tank		1.4	3.75	AI-92 Engine lubrication system
		1.6	3.75
		1.8	3.75
		apI sl (Ilsac gf-III) grade sae 5w-30	6.2
Engine cooling system		1.4	7.2	A mixture of water and high-quality silicate-based antifreeze (year-round coolant)
		1.6	7.2
		1.8	7.5
		apI sl (Ilsac gf-III) grade sae 5w-30	8.0
Automatic transmission	AISIN 81-40LE (1.6)		5.77 ± 0.2	esso jws 3309 or total flUId III g
	ZF 4HP16 (1.8)		6.9 ± 0.2	esso lt 71141 or total atf h50235
	AISIN 55-51LE (2.0S DSL)		6.94 ± 0.15
Manual transmission	Gasoline engines		1.8	sae80w (Extreme cold zone: sae 75w)
	apI sl (Ilsac gf-III) grade sae 5w-30		2.1
Brake system			0,5	DOT 3 or DOT 4
Power steering			1,1	DEXRON II-D or DEXRON III

How much and what to fill a Chevrolet Lacetti with

Engine lubrication system

In accordance with the regulations Maintenance should be changed every 15 thousand km engine oil. The procedure is performed with the engine not running immediately after the trip. Recommended use original oil- synthetics 5W-30. Refill volume for different engines differs - from 3.75 to 6.2 liters.

Fuel system

Volume fuel tank– 60 l. The manufacturer recommends refueling with unleaded gasoline with an octane rating of at least 92 or 95.

Changing the oil in the Lacetti gearbox is a mandatory procedure. After 60 - 80 thousand km, the liquid loses its properties - viscosity and so on. In regions with harsh climates, the frequency is reduced to 40–50 thousand km.

Choose transmission oil necessary depending on the type of gearbox. For automatic use esso jws 3309 or total flUId III g, esso lt 71141 or total atf h50235, mechanical - sae80w (Extreme cold zone: sae 75w).

Brake system

Replacement brake fluid carried out once every two years. Suitable DOT 3 or DOT 4. Refill volume – 0.5 l.

Cooling system

Replacement frequency is 100 thousand km or once every three years. A mixture of water and high-quality silicate-based antifreeze (year-round coolant) is used. The filling volume directly depends on the engine type 7.2 - 8.0 liters.

Replacing the Lacetti brake fluid is a very necessary procedure. Moreover, replacing the brake fluid yourself is not particularly difficult.

It is also worth noting that hydraulic drive The brakes and hydraulic clutch drive on the Chevrolet Lacetti are fed from the same reservoir, so when replacing fluid in the hydraulic brake drive, it is advisable to change the brake fluid in the clutch release drive as well.

Working brake system Chevrolet Lacetti dual-circuit, diagonal. Each of the Lacetti brake circuits includes brake mechanisms of two wheels: one front and one rear, located diagonally on the car. If one of the circuits fails, the second circuit, although with less efficiency, will ensure that the car stops.

Why change brake fluid?

It is recommended to change the brake fluid every 2-3 years, depending on the age of the car and the condition of the brake system as a whole. Those. The older the car, the more often it is advisable to change the brake fluid. Also, if the liquid changes color prematurely, then it must be changed without waiting for a certain period.

The most important answer to the question - why change the brake fluid - is that brake fluid is hygroscopic. Simply put, it absorbs moisture. And this is very, very bad for two main reasons.

Firstly, this leads to increased corrosion of the brake system elements.

Secondly, the boiling point of the brake fluid decreases sharply. The following can be read on the brake fluid container:

It can be seen that in just one year the boiling point decreases by 30-40%!

I think it makes no sense to give further arguments in favor of regularly replacing brake fluid.

Step-by-step replacement of Lacetti brake fluid

To work, you will need an assistant, a 10 mm spanner, and also:

Rubber bulb or syringe;
- transparent vinyl tube with an internal diameter of 4-5 mm, suitable for a dropper;
- container for draining used brake fluid;
- fresh DOT4 brake fluid. The Lacetti brake system contains 0.5 liters of fluid. But you buy at least 1 liter for replacement;
- inspection hole or overpass (preferably).

1. Unscrew the cap of the main tank brake cylinder Chevrolet Lacetti and use a syringe or rubber bulb to remove all the old brake fluid

2. Fill the tank with fresh liquid to the top edge.

Important:
To prevent air from entering the hydraulic drive of the brake system when replacing brake fluid, make sure that its level in the reservoir does not fall below the “min” mark.

3. On the rear right wheel we find the bleeder fitting, clean it of dirt and put a transparent tube on it. It is advisable to apply WD-40 to it, otherwise these fittings tend to “stick”. We lower the second end of the tube into a container for waste liquid.

4. An assistant slowly presses the brake pedal (about 5 presses at intervals of 1-2 seconds) and holds the pedal pressed. At this moment you unscrew the fitting 3/4 turn. Liquid should begin to drain from the fitting through the tube until the brake pedal reaches the floor. After this, tighten the fitting. The assistant should not release the pedal until you tighten the fitting!

Note! It happens that when you unscrew the fitting, the liquid does not flow through the tube. Especially if you are overdue for a brake fluid change. This means that the inner hole of the fitting is clogged. It is necessary to unscrew the fitting completely and clean the hole. Then screw the fitting into place and continue bleeding the brake system.

Repeat this sequence again until fresh liquid begins to come out of the tube (you can identify it by color).

5. Then we carry out this procedure in sequence - left rear, right front, left front. And carefully monitor the brake fluid level!

I'll say a few words about the sequence of pumping calipers. Some pump diagonally, some from far to near... I think there is not much difference. I tried this and that. The result is always the same. Therefore, I do it the way that is convenient for me and as I am used to the old fashioned way - right rear, left rear, right front, left front.

Therefore, decide for yourself in what order to do this.

Here's the last caliper bleed

After fresh and clean brake fluid comes out of all the fittings, add it to the level in the reservoir, close the reservoir cap and do a test drive, paying attention to the operation of the brakes. After the trip, take a control measurement of the level in the tank.

Here is a video about changing brake fluid

Possible problems with calipers and their solutions

That's all. Take care of yourself and good luck on the roads!

Many owners of Chevrolet Lacetti or Cruze cars are interested in the question - what brand of brake fluid GM 93160363 or 1942421 should be poured into the braking system?

Nowadays, in order to add brake fluid, you do not need to go to the dealer at all. Instead, we purchase brake fluid from a store or a reliable supplier by part number. Remember the markings:

93160363 - GM brake fluid markings
1942421 - opel brake fluid marking

The brake fluid of both types is absolutely the same, but is produced for different conveyors by Adam Opel AG, Russelsheim Germany.

The brake fluid for a Chevrolet Lacetti or Cruze is class DOT-4, light orange in color and packaged in a white plastic sealed container of 0.25/0.5/1 liter. The canister has a transparent scale by which you can determine the color and amount of liquid in the canister. The stopper is detachable, which allows you to check whether the canister has been opened before. The front side is marked with month and year markings indicating the last opportunity to open and use this brake fluid canister.

Many car enthusiasts are a little worried about the labeling of the canister. Remember again - brake fluid marked 93160363 is absolutely identical to marking 1942421. They can be interchanged and mixed with each other! The average price of a 0.5 liter canister of brake fluid GM 93160363 or 1942421 at retail is from 410 to 523 rubles. Its cost in an online store (for example, EMEX) is from 280-300 rubles with a delivery waiting period of 2 days. Closest recommended analogues: FEBI 21754, Seiken BF405L, SWAG 10921754 and AD LFS1. Brake fluid

domestic producers

You can't fill it.

The Chevrolet Lacetti hydraulic brake system has two circuits, including an ABS system. Each of these car circuits ensures the braking of the wheels of two mechanisms located diagonally on the car. The car also has one reservoir responsible for supplying working fluid, both for the clutch system and for the vehicle. The correct performance of the brakes is maintained not only by the need to change the pads, but also by replacing the brake fluid (BF) on time, according to the Lacetti regulations. How to do this - look at the photo. According to the instructions for use operating fluids for Chevrolet Lacetti, the brake and clutch hydraulic drive system should be filled with

0.5 liters brake fluid..

The manufacturer allows the use of brake fluid that meets the specification requirements FMVSS116 and DOT4 standard Some manuals talk about using DOT5 on a Chevrolet Lacetti. It should be mentioned that the same instructions indicate which brake fluid should be used, the name of which is indicated on the brake master cylinder (MBC) reservoir. Secondly, DOT5 brake fluid is not compatible with DOT3, DOT4+, or DOT4 and, moreover, in cars with

The original General Motors brake fluid has article number 93160363. A similar replacement will be the “BRAKE FLUID” brake fluid from Opel, catalog number 1942421, produced by GMotors for Opel cars. The price of this working fluid 450 rubles.

Also available wide range TZ from other manufacturing companies Fenox “SBrake” SBF4005, Miles “BRAKE FLUID” EBF455, Hella-Pagid “BRAKE FLUID” 8DF355360011, Miles “BRAKE FLUID” EBF910. The price of these liquids varies from 100 to 200 rubles.

Prices are current for autumn 2017 for Moscow and the region.

How to change brake fluid on a Chevrolet Lacetti

To do this, you will have to pump out the old fluid from the tank, add fresh fluid, create pressure in the system (by pumping the pedal or a special device), put a hose on the fitting (one end of which will be in a transparent bottle with liquid), unscrew the bleeder fitting on the wheel caliper, wait until it goes fresh brake fluid without air. It is very important to follow the pumping scheme.

We extract air from the system with the engine off, first from one circuit, and then from the other, following the sequence of bleeding the brakes: the right rear wheel; left front wheel; left rear wheel; right front wheel.

Replacement instructions DIY TJ:

1. Unscrew the cover of the GTZ tank.
2. Using a syringe we pump out working fluid from the tank.
3. We pour new fuel oil up to the lower rim in the neck of the tank.

   It is important to prevent air from entering the vehicle’s hydraulic system. To do this, you must ensure that its level in the tank does not drop below the “MIN” mark.

4. The brakes must be bled with a helper. We clean the wheel brake cylinder fitting from dirt and remove the protective cap.
5. Using a “10” wrench, loosen the tightening of the bleeder fitting.
6. We put it on one end of the vinyl hose and lower the other into a bottle half filled with brake fluid.
7. The helper must depress the pedal 4-5 times, swinging the TJ and hold it in the lower position.
8. We continue to unscrew the fitting with a wrench ½-¾ of a turn. In this case, old fuel fluid and air bubbles should come out of the end of the tube, and in the meantime the pedal is pressed all the way.
9. As soon as the fuel fluid stops flowing, tighten the fitting and release the pedal.
10. We carry out the above steps until a new brake fluid comes out of the hose. In this case, the pedal travel should not exceed half the distance to the floor.
11. We carry out similar actions on another wheel of the same circuit (according to the diagram).
12. In the same way we bleed the brake mechanisms of the wheels of another circuit (according to the diagram).

To work you will need the following:

• assistant;
• transparent tube with a diameter of 4-5 mm;
• transparent bottle;
• special key “10 mm”;
• container for draining fuel fluid;
• syringe;
• new brake fluid class DOT4.

We replace brake fluid in a Chevrolet Lacetti.

Unscrew the cap of the brake fluid reservoir.

We pump out the brake fluid with a syringe, but not all of it; it is advisable to leave a little at the bottom so as not to air the system.

Take new fluid and fill it to the MAX mark.

We go down and remove the wheel.

Remove the rubber protective cover. We put a hose on the bleeder fitting to drain the brake fluid.