Lubes em Foco Magazine – issue 95
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Engines, whether combustion or electric, generate considerable heat. Weather extremes, whether excessive heat or snow, also impact their operation. Efficient temperature management is crucial, and coolant, also known as radiator fluid, is a key ally in automotive maintenance, preventing overheating, severe damage, and premature failure.
Coolant is a highly complex chemical engineering element, combining thermal, chemical, and material compatibility properties. Choosing the right technology, complying with regulations, and performing preventive maintenance are crucial to the system’s reliability and durability.
But how does it work? In a closed system, the liquid circulates between the hot parts of the engine and radiator for efficient cooling, based on its physical and chemical properties.
Every minute, all components in the system are touched 25 times by the coolant. In light vehicles, approximately 150 liters of coolant are pumped per minute, and one-third of the engine’s combustion energy is released into the atmosphere through the coolant and radiator. Vehicles typically maintain a steady temperature of around 90°C, which can vary in specific situations. Internally, the temperature can reach 290°C for seconds in some parts of the system, a phenomenon called a hotspot. During this phenomenon, the coolant evaporates and liquefies again within seconds. Additives in the coolant support this effect, keeping the system protected from corrosion and cavitation (formation of vapor bubbles).
Why not just water?
The first coolant, developed and patented by Dr. Otto Jordan in 1926 and launched by our company in 1929, was created to replace water. Although a perfect coolant in theory, water expands when it freezes, turns to vapor at 100°C, and contributes to the corrosion of metal engine parts. These effects impair engine performance and posed a challenge for the scientist.
With nearly 100 years of experience, investing in quality products and applying them correctly are direct factors in vehicle savings and safety. Our product line has evolved to meet the technological needs of the automotive market. The purpose of a coolant is to maintain the water’s good heat transfer, eliminating its negative effects.
A quality coolant is composed of water, glycol, and additives that ensure engine protection and performance:
- Prevents cavitation and corrosion: Effective inhibitors combat the formation of vapor bubbles and metal degradation.
- Material compatibility: To prevent degradation and leaks, it must be compatible with polymers, elastomers, and rubbers.
- Low foaming: Reduces heat exchange efficiency and circulation problems.
- Deposit prevention: Prevents radiator and system blockages.
- High-temperature stability: Maintains properties under high-temperature conditions.
- Excellent heat transfer: Essential for maintaining engine temperature.
- Hard water compatibility: Prevents scale formation.
- Freeze protection: Prevents structural damage in cold climates.
Coolant technologies:
There are several technologies to meet different vehicle needs:
- Inorganic Technology (IAT): Uses corrosion inhibitors based on inorganic salts. Used in light and heavy-duty vehicles, it offers a limited service life. (We do not work with this technology).
- Organic Acid Technology (OAT): Designed for diesel and gasoline vehicles, it offers excellent corrosion protection and high durability for all types of light and heavy-duty vehicles. Based on neutralized organic acids and azoles, it is free of silicates, amines, borates, nitrites, and phosphates, meeting Asian, American, and European OEM specifications. It contains corrosion inhibitors based on neutralized organic acids and is excellent for protecting aluminum. Its service life is 4 to 5 times longer than inorganic technology.
- Hybrid Technology (H-OAT): Combines the benefits of inorganic and organic technologies, providing advanced protection.
Like other vehicle components, coolants must meet international technical standards. In Brazil, they follow ABNT standards, aligned with international standards such as ASTM, SAE, British Standard, Japanese (JIS) and Chinese (GB) standards, ensuring global compatibility and quality.
The importance of maintenance and correct application
There are important recommendations for coolant maintenance. The main one is not to mix different types of technology, as the performance of the additives can be limited or interfere with, reducing effectiveness and drain intervals.
When performing repairs, it is important to clean the cooling system and completely replace the coolant. We recommend replacing the coolant every 3 or 4 years, but it is important to follow the vehicle manufacturer’s instructions. If using a concentrate, check the label for dilution requirements, as the correct proportion of water is essential. Finally, disposal must be carried out by qualified companies, ensuring environmental protection.
Incorrect use or choosing low-quality products can cause serious system problems:
- In the radiator: water pump leak, corrosion, broken pump seal, blocked pipes or radiator, broken thermostat.
- In the engine: overheating, loss of performance, pressure in the cooling system.
- In parts: damage such as porosity in rubber and plastic parts.
The New Frontier: Coolants for Electric Vehicles
With increasing electrification, electric vehicles present unique challenges for coolants regarding thermal management due to the presence of sensitive electronic components and high-voltage batteries. Although they lack a combustion engine, EVs rely on sophisticated thermal management systems.
The lithium-ion battery, the heart of EVs, generates heat during charging and discharging. The ideal operating temperature is between 20-30°C. Outside this range, performance, lifespan, and safety can be compromised. Low temperatures decrease kinetics; high temperatures increase degradation and can lead to thermal runaway (above 75°C).
Most OEMs, electric vehicle manufacturers, use the same water-glycol-based coolants as internal combustion vehicles in indirect cooling systems, where the fluid does not come into direct contact with the battery cells. The presence of water in contact with the batteries could generate hydrogen and oxygen, increasing the risk of overheating, fire, and explosion. However, there are engineering solutions/materials used in EVs that protect the batteries in the event of accidental direct contact. Recognizing the specific needs of EVs, our company developed a chemical solution for this application: coolants with a focus on low electrical conductivity, offering additional safety benefits. These solutions optimize thermal performance, material compatibility, and safety in high-voltage environments.
The use of a low-conductivity coolant, in the event of accidental direct contact with the battery, reduces the evolution of the water-hydrogen reaction by 98%, saving time for passengers to exit the vehicle or for repairs.
Coolant, far from being a mere “liquid,” is a complex engineering component vital to the performance and longevity of any vehicle. Whether in combustion engines, protecting against corrosion and overheating, or in electric vehicles, ensuring excellent thermal management of the system as well as battery safety and efficiency, its continuous evolution is essential for the advancement of mobility. Choosing a quality product that meets OEM specifications and requirements, as well as proper maintenance, are essential investments for the health and durability of your vehicle.
