Note. The following procedure describes the procedures performed on a monthly basis. For other fluid level checks, see the appropriate Service Specific Sections below. Regardless of the intervals stipulated by the Schedule, try not to disregard the occurrence of fluid leaks under cars - such signs indicate the presence of faults that need to be fixed immediately.
Attention! When checking the level of any working fluid, the car must be located strictly horizontally!
Fluids are an integral part of lubrication, cooling, braking and windshield washing systems. Due to the normal consumption and tendency to contamination during the operation of the vehicle, it is necessary to periodically check the condition / levels and replace the working fluids - read the requirements of the Specifications for the types of compositions used and the fill volumes of the respective systems.
Engine oil
Visual control of leaks
1. With noticeable oiling of the power unit and high oil consumption, carefully inspect the places where leaks are most likely to develop:
- The sealing element of the engine oil filler cap, - check for cracks and other mechanical damage;
- Components of the crankcase ventilation system (in particular - the ventilation hose from the cylinder head cover to the intake duct);
- cover gasket (ek) cylinder heads;
- head gasket (OK) cylinders;
- Sealing element of the drain plug of the engine crankcase;
- Oil filter gasket, - carefully examine the place where the filter fits on the mounting flange;
- Oil pan gasket;
- Front and rear crankshaft seals.
2. Wrap the generator in polyethylene, spray the engine with a normal cold cleaner, - then, after a short time - wash the unit in a car wash.
3. Sprinkle the joints of the mating surfaces and the sealing elements of the power unit with lime or talc from the outside.
4. Check oil level, correct if necessary (see below).
5. During the short (about 30 km) travel (preferably on the highway) warm up the engine to normal operating temperature - hot oil is characterized by increased fluidity and seeps through leaks more easily.
6. Park the car in a safe place and, highlighting yourself with a lamp, examine the engine in order to localize sources of oil leaks. Eliminate the causes of the development of leaks.
Level check
Note. The maximum allowable consumption of engine oil is 1 l/1000 km, the actual level of oil consumption depends on the driving style - frequent driving at high engine speeds leads to an increase in oil consumption.
Note. Information on the principle of operation of the engine oil level warning lamp is given in Section Instrument cluster, meters and control lamps and indicator lights.
1. A warning lamp built into the ignition lock assembly warns the driver of a dangerous drop in the level of impellent oil (see Section Instrument cluster, meters and control lamps and indicator lights). The oil level/temperature/quality sensor is placed under the vehicle, in the right front corner of the engine oil pan (see resist. illustration).
Note. ML 230 models use an oil level switch (S43).
2. Checking the level of impellent oil is carried out using a dipstick threaded into the guide tube and lowered into the engine to the lowest point of the oil pan of its crankcase. The oil level should be checked before the first trip of the day, or about 5 minutes after the engine has been stopped. If the check is performed immediately after turning off the engine, the results will not adequately reflect the situation, as part of the oil will be distributed to the internal galleries and engine components.
Checking the engine oil level
3. Remove the dipstick from the guide tube and dry its blade with a clean cloth or paper towel. Insert the dipstick back into the tube until it stops, then remove it again. After examining the probe blade, estimate the size of the area wetted with oil. The oil level should be between the upper and lower marks on the dipstick blade. If necessary, top up the engine with the appropriate amount of oil of the required grade.
The oil level must be between the lower (MIN) and top (MAX) marks on the blade of the probe
4. Lowering the level beyond the lower limit of the permissible range leads to the development of engine oil starvation, which is fraught with serious mechanical damage to the latter. Try also not to overfill the oil above the upper mark, as this can lead to throwing spark plugs or failure of the power unit seals as a result of excessive pressure buildup.
5. In order to fill the engine with oil, it is necessary to remove the threaded filler cap. Use a funnel or an oil can with a long spout to avoid splashing oil when filling it into the engine. After filling in oil, screw on and firmly tighten the filler cap, then start the engine and carefully inspect the drain plug and the surface of the oil filter mating with the block for signs of leakage. Stop the engine, wait 5-10 minutes for the oil to drain into the sump, then check the level again.
Note. Excess oil must be drained or pumped out of the crankcase - an excessive level of impellent oil can cause failure of the catalytic converter. Track reliability of a tightening of a cover of a jellied mouth.
6. Checking the engine oil level is an important preventative engine maintenance procedure. A constantly low level indicates the presence of oil leaks as a result of failed oil seals, damaged seals, worn piston rings or valve guides. If the oil resembles milk in color or consistency, or there are drops of water in it, this indicates a possible damage to the cylinder head gasket, or the formation of cracks in the body of the head (OK) or block. The check must be made without delay. When measuring the oil level, always also check its condition. Using your thumb and forefinger, remove traces of oil from the dipstick blade - if there are small metal particles in it, the oil must be replaced (see Section Changing the engine oil and oil filter).
Engine coolant
Attention! Do not allow antifreeze to come into contact with exposed areas of the body and painted surfaces of the car. Wash off accidental splashes with plenty of water without delay. Remember that antifreeze is a highly toxic liquid and getting it into the body, even in small quantities, is fraught with the most serious consequences, even death. Never leave antifreeze stored in a loosely closed container, immediately collect spilled coolant on the floor. Remember that the sweet smell of antifreeze can attract the attention of children and animals. Consult with local authorities about ways to dispose of used coolant - in many regions of the world there are special points for receiving various kinds of waste. Never drain old coolant down the drain and onto the ground!
Note. Recently, non-toxic grades of antifreeze have been developed, however, they must also be disposed of in an organized manner.
1. All vehicles covered in this manual are equipped with an overpressure compensation type cooling system. The white plastic expansion tank is located in the engine compartment and is connected by a hose to the radiator. As the engine warms up during operation, the expanding coolant fills the reservoir. When the engine cools down, the coolant automatically flows back into the cooling system, which maintains a constant value of its level. A warning lamp included in the instrument cluster warns the driver of a dangerous drop in the coolant level (see Section Instrument cluster, meters and control lamps and indicator lights). The coolant level switch is located at the bottom of the expansion tank of the cooling system.
2. Checking the coolant level in the tank should be done regularly, with the vehicle in a strictly horizontal position and the engine off. When cold, the coolant level should reach the mark «COLD LEVEL», applied to the translucent wall of the tank. After the engine warms up, the coolant level rises by approximately 1.0 -1.5 cm. If necessary, make the appropriate adjustment - add only the liquid of the required composition (see Specifications).
3. Having made a short trip on the car, measure the coolant level again, a slight adjustment can be made by adding distilled water, however, it should be remembered that frequent additions of water lead to dilution of antifreeze, so it is wiser to always add a mixture of the required composition to the system.
4. The regular need to adjust the coolant level indicates the presence of its leaks (external or internal), - carefully examine the external condition of the radiator, connecting hoses, filler cap, drain plugs and water pump (see Section Checking the functioning of the cooling system and frost resistance of the coolant, changing the fluid). If it is not possible to identify the source of the leak, check the tightness of the caps of the expansion tank and radiator in a workshop.
5. Removing the covers of the components of the cooling system should be done after the engine has completely cooled down. Wrap the cover with a rag and unscrew it to the first point of weakening of resistance - if steam or coolant begins to escape from under the cover, let the engine cool a little more, and only then remove the cover completely.
6. It is also necessary to check the condition of the coolant, it must be relatively clean. If the liquid has a reddish-brown color, it must be drained, then the cooling system path must be flushed and filled with a fresh mixture of the required composition. Even if the coolant looks normal, the corrosion inhibitors included in its composition lose their effectiveness over time, therefore, in any case, replacement should be carried out in accordance with Schedule of ongoing maintenance.
7. Checking the resistance of the coolant to freezing is done using a hydrometer.
Brake fluid
Attention! Brake fluid can harm your eyes and damage the painted surfaces of your vehicle, so be very careful when handling it. Do not use brake fluid that has been exposed for a long time or is more than one year old. Brake fluid tends to absorb moisture from the air, which can lead to a dangerous loss of brake system performance. Use only the recommended type of brake fluid. Mixing different types of fluid can cause brake system failure.
1. The master cylinder of the brake system is installed in the rear left corner of the engine compartment. A drop in the driver's brake fluid level is warned by the operation of a warning lamp built into the instrument cluster (see Section Instrument cluster, meters and control lamps and indicator lights), the float switch of which is built into the cover of the reservoir of the main brake cylinder (GTZ).
The brake fluid level switch is built into the GTZ reservoir cap
2. The brake fluid level is checked visually and must be between the marks «MAX» And «MIN», applied to the translucent walls of the GTZ tank. If necessary, make the appropriate adjustment by adding the required amount of fresh fluid through the reservoir neck - before unscrewing the cover, wipe the reservoir from the outside to prevent dirt from entering the hydraulic path.
Note. Do not overfill the tank with liquid.
3. With the cover removed, check the liquid and the walls of the GTZ reservoir for signs of contamination. If the presence of rust particles, dirt or water drops is detected, the fluid should be replaced and then «pumping» braking system.
4. After completing the adjustment/replacement, check that the reservoir cap is even and tight.
5. The gradual lowering of the liquid level in the GTZ reservoir is due to the wear of the brake pads. There is no need to add liquid if its level does not fall below the mark «MIN», - if necessary, check the condition of the friction linings of the pads, - replacement of the pads will lead to automatic leveling.
6. If the need to adjust the brake fluid level occurs regularly, you should carefully check the hydraulic path of the brake system for signs of leaks without carefully inspecting the condition of the calipers / wheel cylinders, GTZ, brake pipes, hoses and their union connections, (see Sections Checking the brake system and Checking the condition and replacing the engine compartment hoses, localizing leaks).
7. When the liquid level in the GTZ tank drops below the mark «MIN» brake system should «pump» (see chapter Brake and auxiliary systems).
Power steering fluid (power steering)
Attention! If the fluid level in the tank has fallen below the zone corresponding to the current temperature range, the hydraulic power steering must be checked by a specialist workshop, since there is a loss of fluid - a simple level correction will not be enough in this case!
Checking the power steering fluid level is carried out at a temperature of about 20°C. The fluid level must be between the marks «MIN» And «MAX» on the walls of the reservoir of the hydraulic power steering system. The total volume of the tank is 1.2 liters.
Windshield/Headlight Washer
Attention! Windshield washer concentrate is highly flammable! Do not use fire, open flames or smoking when handling windshield washer concentrate.
1. The windshield washer fluid reservoir is installed in the left front corner of the engine compartment, behind the left headlight unit and is equipped with a filler neck with a bayonet type cap. The capacity of the tank is about 7.6 liters (see Specifications).
Location of the washer fluid/headlight lens reservoir in the engine compartment (for all models)
2. A warning lamp built into the instrument cluster warns of a drop in the driver's fluid level, - the control lamp sensor-switch is mounted in the upper part of the washer fluid reservoir.
3. In temperate climates, the system can be filled with normal water, but it is recommended to add glass cleaner to the water (summer MW concentrate is labeled S). The tank should be no more than two-thirds full, so that there is free space in case the water expands when it freezes. In areas with cold climates, a special windshield washer concentrate should be used (W marking), which lowers the freezing point of the liquid, which can be purchased at any auto accessories store. It is usually sold in concentrated or prepared form. If you purchased concentrated antifreeze, mix it with water according to the manufacturer's instructions on the package.
Attention! Do not use antifreeze in the cooling system - it will damage the painted surfaces of the car!