A modern car is a complex mechanism in which many different working compounds circulate to ensure its smooth operation. Technical fluids perform lubrication, cooling, power transmission or cleaning functions, and ignoring their condition can lead to costly engine or transmission repairs. Owners often know about motor oil, but forget about power steering hydraulics or specific compounds for safety systems.
In this article we will analyze in detail a complete list of all the necessary compounds that your vehicle requires and determine the frequency of their replacement. Timely service - this is not just a recommendation in the service book, but a necessity that extends the life of components by hundreds of thousands of kilometers. You will learn the difference between classic water and antifreeze and why you should not mix different types of brake fluids.
It is important to understand that each composition has its own unique chemical properties and service life. Mixing organic and inorganic based fluids in a cooling system can result in the formation of a gel-like deposit that will completely clog the radiator in a matter of days. Let's look at the main categories of consumables, without which the operation of the machine is impossible.
Motor oils: the basis of engine life
The main element in the list of technical fluids is motor oil. It creates a protective film on rubbing parts, removes heat from the piston group, cleans internal surfaces of carbon deposits and prevents corrosion. Viscosity and the chemical composition of the oil are selected strictly in accordance with the requirements of the engine manufacturer specified in the specification API or ACEA.
There are three main types of oils: mineral, semi-synthetic and synthetic. Mineral products are obtained by distilling petroleum and have unstable properties at extreme temperatures. Synthetics are created artificially and retain their properties both in severe frost and when overheated, but they are much more expensive.
- 🛢️ Base oil: the basis that determines 70-80% of the properties of the product (hydrocracking, PAO, esters).
- ⚗️ Additive package: chemical additives that improve cleaning, anti-corrosion and anti-wear properties.
- 🌡️ Viscosity index: an indicator characterizing the change in oil thickness depending on temperature.
Replacement intervals depend not only on mileage, but also on engine hours. If you often sit in traffic jams or use the car for short trips, the oil life is halved. In such conditions, it is recommended to change the lubricant every 7-8 thousand kilometers, even if the manufacturer allows 15 thousand.
⚠️ Attention: It is strictly forbidden to add oil with a different chemical composition (for example, mineral oil to synthetics) without first flushing the system. The reaction can cause additives to coagulate and form hard deposits, leading to oil starvation and shaft seizure.
Coolants: overheat protection
The engine cooling system operates in an aggressive environment of high temperatures and pressure. The main task antifreeze is to remove heat from the cylinder block and prevent liquid freezing in winter. Unlike water, special compounds do not expand during crystallization, which saves the engine block and radiator from ruptures.
Modern coolants contain ethylene glycol or propylene glycol, distilled water and an additive package. Additives protect metal parts from corrosion, and rubber pipes from swelling. There are different classes of antifreeze: G11 (silicate), G12/G12+ (carboxylate) and G13 (lobrides based on glycerin).
Each type has its own color, although this is not always a strict standard, so you need to focus on the manufacturer’s tolerances. Silicate liquids form a protective layer throughout the system, but over time they crumble and clog the stove radiator. Carboxylate ones act precisely, only in places where corrosion occurs, and last much longer.
What happens if you pour water into the radiator?
Water contains salts and minerals, which when heated form scale on the walls of the cooling jacket. This impairs heat dissipation, which leads to local overheating of the engine. In addition, water freezes at 0°C, expanding in volume by 10%, which is guaranteed to burst an aluminum block or radiator.
Check the coolant level only when the engine is cold. Opening the expansion tank cap on a hot engine will result in the release of boiling water under pressure and serious burns. If the level is constantly dropping and there are no external leaks, it is possible that antifreeze is entering the cylinders through a blown cylinder head gasket.
Brake system and hydraulics
Brake fluid (DOT) is a key element of vehicle safety. It transmits force from the brake pedal to the wheel calipers. The main feature of this liquid is hygroscopicity, that is, the ability to absorb moisture from the air. Over time, the water content in the system can reach a critical 3-4%.
During active braking, the brake discs and calipers heat up to high temperatures. If a liquid has accumulated a lot of water, it will boil, forming vapor locks. Steam, unlike liquid, is compressed, and the brake pedal will simply “fall” to the floor, leaving the car without brakes.
- 💧 DOT-3: Glycol base, used on older cars, quickly absorbs moisture.
- 🔥 DOT-4: the most common type, has a higher boiling point and improved lubricating properties.
- 🏎️ DOT-5.1: Glycol fluid for sports cars with a high boiling point, compatible with DOT-4.
Brake fluid must be changed every 2 years or 40-60 thousand kilometers, regardless of its appearance. It is better to carry out the procedure in a specialized service using a bleeding device to completely remove air and old mixture from all circuits of the system.
☑️ Checking the brake system
Transmission oils and ATF fluids
The transmission also requires good lubrication to reduce friction between the gears and dissipate heat. In manual transmissions (Manual transmission) viscous oils are used to create a durable film. In automatic boxes (Automatic transmission) special liquid is used ATF (Automatic Transmission Fluid), which acts not only as a lubricant, but also as the working fluid of the torque converter.
ATF fluid transmits torque from the engine to the gearbox, cools the clutches and ensures the operation of the valve body. It has a completely different chemical composition and color (usually red or green) than motor oil. It is strictly forbidden to mix them or use them for other purposes.
In CVT boxes (CVT) and robotic transmissions (DSG) their own unique types of liquids are used. For example, for CVT The friction between the chain and the variator cones is critical, which is ensured by special additives. Using the wrong oil will cause the chain to slip and quickly destroy the cones.
| Box type | Liquid type | Replacement interval (km) | Features |
|---|---|---|---|
| Manual transmission | Gear oil (75W-90) | 60 000 - 90 000 | High viscosity, anti-scuff |
| Automatic transmission (torque converter) | ATF (Dexron, Mercon) | 40 000 - 60 000 | Low viscosity, foam resistance |
| CVT (CVT) | CVT Fluid | 40 000 - 60 000 | Specific coefficient of friction |
| DSG (Robot) | DSG Oil | 60 000 | Separately for mechatronics and clutch (sometimes) |
When changing the oil in an automatic transmission using the partial drain method (through a plug), only 40-50% of the volume is renewed. A complete replacement requires a hardware procedure or triple partial replacement at 200 km intervals.
Fluids for comfort and control systems
A modern car is equipped with many hydraulic systems that facilitate control and increase comfort. First of all this power steering (Power steering). It often uses a special power steering oil or, in some cases, a compatible ATF as the working fluid. The level and condition of the fluid in the power steering reservoir must be checked regularly, as leaks can lead to pump failure.
It is also worth mentioning windshield washer fluid. In winter, it is critical to use low-freezing point formulations based on isopropyl alcohol. Water frozen in the reservoir or pipes can rupture the plastic or damage the electric washer pump. In summer, you can use water with added shampoo to better remove insects.
In diesel cars and modern gasoline cars with direct injection it is used AdBlue (urea). This is a technical urea solution that is injected into the exhaust system to neutralize nitrogen oxides. AdBlue consumption is approximately 1-2 liters per 1000 km, and its absence can lead to the electronics blocking the engine from starting.
⚠️ Attention: Never pour AdBlue into the fuel tank of a diesel engine! This will cause immediate and irreversible damage to the fuel system and will require replacement of the tank, pump and injectors. The necks of the tanks have different diameters, but when refueling from a canister, be extremely careful.
Lubricants and special compounds
In addition to fluids circulating in closed circuits, the car requires the use of various greases and sprays. Graphite and lithium Lubricants are used in wheel bearings, ball joints and steering ends. They work under conditions of high loads and moisture.
Special dielectric lubricants are used to service electrical contacts, connectors and spark plug tips. They prevent contact oxidation and spark breakdown. To eliminate squeaks in plastic panels and rubber door seals, silicone lubricants are used, which also protect the rubber from drying out in the sun and frost.
Penetrating lubricants (for example, WD-40 and analogues) deserve special attention. They are used to decarbonize rusted threaded connections. However, it is worth remembering that this is not a lubricant, but rather a rust solvent and moisture displacer. After using them, it is advisable to lubricate the connection with grease.
Correct selection and timely replacement of all technical fluids increases the life of the car by 30-40% and maintains its liquidity in the secondary market.
Frequently asked questions (FAQ)
Is it possible to mix antifreeze of different colors?
Color is not a guarantee of compatibility. You can only mix liquids of the same class (for example, G12+ with G12++), even if the colors are slightly different. Mixing silicate (G11) and carboxylate (G12) antifreeze will lead to sedimentation and loss of properties.
How often should brake fluid be changed?
The recommended replacement interval is once every 2 years. This is due to the fact that the liquid is hygroscopic and over time becomes saturated with water, which reduces the boiling point and causes corrosion of system elements.
What happens if you pour oil into the engine above the level?
Exceeding the oil level above the maximum mark on the dipstick is dangerous. The crankshaft will begin to foam the oil, which will lead to foam entering the lubrication system, reducing pressure and possibly squeezing out the oil seals.
Do I need to flush the engine when changing the oil?
If you use high-quality oil and change it regularly, flushing is not required. Flushing oils only make sense when switching from mineral to synthetic or if carbon deposits and deposits have been found in the engine.