Every Car Fluid Explained in 15 Minutes

Coolant: The Engine's Thermostat

• ❄️ Coolant prevents engine overheating by absorbing heat and dispersing it through the radiator.
• 🌡️ It's typically a 50/50 mix of water and antifreeze, with split ratios adjusted for climate to optimize boiling and freezing points.
• 🔄 The thermostat regulates coolant flow, opening when the engine is too hot and closing when it's too cold.
• ⚠️ Coolant degrades over time and should be changed according to the manufacturer's timeline.

Windshield Wiper Fluid: Simple but Essential

• 💧 Windshield wiper fluid is composed of water, a surfactant (soap), and methanol to aid drying.
• 🧼 Its primary function is to clean the windshield for better visibility.

Power Steering Fluid: A Fading Hydraulic System

• 🚗 Power steering fluid is becoming less common with the rise of electric power-assisted steering (EPAS) systems.
• ⚙️ In hydraulic systems, it circulates under pressure to assist steering, reducing the effort required to turn the wheel.
• ⚠️ Low fluid levels can cause a moaning sound when turning, and the fluid should be flushed every 30,000 miles to prevent wear.

Engine Oil: The Lifeblood of Your Engine

• 🛢️ Engine oil lubricates, cleans, prevents corrosion, and aids in cooling by reducing friction between moving parts.
• 🧪 It contains additives for cleaning, anti-corrosion, and oxidation prevention.
• 📈 Viscosity ratings (e.g., 0W-20) indicate the oil's flowability at low and high temperatures, crucial for optimal engine performance.
• 💎 Synthetic oil generally offers better performance and longevity than conventional oil but is more expensive and can potentially increase leaks in older vehicles.

Brake Fluid: Critical for Stopping Power

• 🛑 Brake fluid transmits hydraulic force generated by the braking system to stop the vehicle.
• 🧪 Composed primarily of glycol ether, it's chosen for its solvency and compatibility with braking system materials.
• 💧 Brake fluid has DOT ratings (e.g., DOT 3, DOT 4, DOT 5.1) based on dry and wet boiling points, which are critical for preventing vapor lock and brake failure.
• ⚠️ Glycol ether absorbs moisture, lowering the boiling point and potentially leading to corrosion and spongy brakes.

Transmission Fluid: Diverse Roles for Drivetrain Health

• ⚙️ Transmission fluid (ATF, manual, CVT) is vital for lubrication, cooling, and hydraulic functions within the transmission.
• 🌟 Automatic Transmission Fluid (ATF) acts as a triple threat, balancing temperature, lubricating, and providing hydraulic components.
• 🏋️ Manual transmission fluid (gear oil) has higher viscosity and superior lubricating properties to handle the heat and friction from shifting and also lubricates the differential.
• ⚡ CVT fluid has very low viscosity to ensure smooth operation of belt and pulley systems, contributing to fuel efficiency.

Fuel: The Engine's Energy Source

• ⛽ Fuel (gasoline) is derived from petroleum hydrocarbons and includes additives for protection.
• 💥 Octane rating measures fuel's resistance to premature ignition (knock) during combustion, which is critical for engine health.
• ⚠️ Using the wrong octane level can cause knocking and damage engine cylinders.