Welcome to the Car Mechanics Hub. Click any topic below to learn how it works. (This page is powered by a reusable JavaScript library.)

[
    {
        "groupTitle": "Section 1: The Engine (Core Components)",
        "topics": [
            {
                "title": "What is an Engine?",
                "explanation": "The engine is the 'heart' of the car. It's an 'internal combustion' engine, which means it creates power by exploding a mixture of fuel and air inside strong metal cylinders.\n\nThis process is called the 4-Stroke Cycle.",
                "example": "The 4-Stroke Cycle:\n1. **Intake**: Piston moves down, sucking in fuel and air.\n2. **Compression**: Piston moves up, squeezing the mix.\n3. **Power**: Spark plug ignites the mix, causing an explosion that forces the piston down.\n4. **Exhaust**: Piston moves up, pushing the burnt gases out."
            },
            {
                "title": "Engine Oil (The Lubricant)",
                "explanation": "Engine oil is the 'lifeblood' of the engine. It's a lubricant that serves two main purposes:\n\n1. **Reduces Friction**: Coats all moving metal parts (like pistons and bearings) so they slide smoothly instead of grinding together.\n2. **Cools**: Carries heat away from the hottest parts of the engine.",
                "example": "Why change it? Over time, oil gets dirty with metal shavings and burnt particles. It also 'breaks down' from heat and loses its ability to lubricate. Old, dirty oil will destroy an engine."
            },
            {
                "title": "The Cooling System (Radiator)",
                "explanation": "The engine's explosions create immense heat. The cooling system (radiator, water pump, thermostat, and hoses) pumps a fluid called 'coolant' (or 'antifreeze') through special passages in the engine to absorb this heat. The hot coolant then flows to the radiator, where air passing through the fins cools it down before it repeats the cycle.",
                "example": "Key Parts:\n• **Radiator**: The big 'grill' at the front that releases heat.\n• **Water Pump**: The pump that circulates the coolant.\n• **Thermostat**: A valve that stays closed when the engine is cold (to help it warm up) and opens when it's hot."
            },
            {
                "title": "The Fuel System (Injection)",
                "explanation": "The fuel system delivers gasoline from the tank to the engine. In modern cars, this is 'Fuel Injection'.\n\n1. A **fuel pump** (in the tank) pressurizes the fuel.\n2. It sends it to a 'fuel rail' (a pipe) at the engine.\n3. **Fuel injectors** (tiny electronic nozzles) spray a fine, precise mist of fuel directly into the cylinder at the perfect moment.",
                "example": "Old vs. New\nThis system replaced the 'carburetor', an old mechanical device that just sucked fuel in with air. Injection is far more efficient and powerful."
            },
            {
                "title": "The Exhaust System",
                "explanation": "The exhaust system has three jobs:\n1. **Collects**: The 'exhaust manifold' collects the hot, burnt gases from the engine's cylinders.\n2. **Cleans**: The 'catalytic converter' uses rare metals to burn off the most harmful pollutants (CO, NOx).\n3. **Quiets**: The 'muffler' uses a series of chambers and baffles to cancel out the loud explosion sounds, 'muffling' them.",
                "example": "Analogy:\nA muffler works like blowing across a bottle, but with many chambers, so the sound waves cancel each other out."
            }
        ]
    },
    {
        "groupTitle": "Section 2: The Electrical System",
        "topics": [
            {
                "title": "The Battery",
                "explanation": "The battery is a 12-volt box that provides the electricity needed to start the car. It powers the 'starter motor', which is a powerful electric motor that turns the engine over. It also powers the lights, radio, and computer when the engine is off.",
                "example": "Key Idea:\nThe battery *starts* the car, but the *alternator* (see next topic) *runs* the car and recharges the battery while you drive."
            },
            {
                "title": "The Alternator (Charging)",
                "explanation": "Once the engine is running, the alternator takes over. It's a mini-generator driven by a belt from the engine. It generates all the electricity the car needs to run (spark plugs, computer, lights, etc.) and also sends electricity back to the battery to recharge it.",
                "example": "Symptom of failure:\nIf your 'alternator' fails, your car will keep running for a short time (using only battery power), but the battery will quickly die and the car will shut down, even while driving."
            },
            {
                "title": "The Starter",
                "explanation": "The starter is a small, powerful electric motor. When you turn the key, it draws a huge amount of electricity from the battery. A small gear pops out and engages the 'flywheel' (a large toothed wheel on the engine), spinning the engine until it can run on its own. This is the 'RRR-RRR-RRR' sound you hear when starting.",
                "example": "Symptom of failure:\nYou turn the key and hear a single 'CLICK' (or nothing), but the engine doesn't turn over. This often means the starter has failed (or the battery is dead)."
            },
            {
                "title": "ECU (The 'Brain')",
                "explanation": "The 'Engine Control Unit' (ECU) is the car's main computer. It's a small box full of microchips that receives data from dozens of sensors all over the car (oxygen sensors, engine speed, temperature, etc.). It uses this data to make millions of calculations per second to precisely control the fuel injectors and spark plugs for maximum efficiency and minimum pollution.",
                "example": "Check Engine Light:\nWhen the 'Check Engine Light' comes on, it means the ECU has detected a problem from one of its sensors (e.g., 'O2 Sensor Failure')."
            }
        ]
    },
    {
        "groupTitle": "Section 3: The Drivetrain (Power to Wheels)",
        "topics": [
            {
                "title": "The Transmission (Gears)",
                "explanation": "The transmission (or 'gearbox') is the link between the engine and the wheels. An engine is only efficient at high speeds (RPMs), so the transmission uses gears to adjust the power. It gives you low-end power to start (1st gear) and high-end efficiency for cruising (5th/6th gear).",
                "example": "Analogy: Bicycle Gears\nIt's the *exact* same as the gears on a 10-speed bike.\n\n• **Low Gear (1st)**: Easy to pedal, but you move slowly. (Used for starting/uphill).\n• **High Gear (5th)**: Hard to pedal, but you move fast. (Used for highway cruising)."
            },
            {
                "title": "Automatic vs. Manual",
                "explanation": "Both are transmissions, they just shift gears differently.\n\n• **Manual**: The driver uses a clutch pedal and a stick shift to manually select the correct gear.\n\n• **Automatic**: The car's computer and a complex system of 'planetary gears' and 'clutch packs' automatically select the best gear for you.",
                "example": "Key Parts:\n- Manual: Clutch, Pressure Plate, Gear Stick\n- Automatic: Torque Converter, Planetary Gears, Valve Body"
            },
            {
                "title": "The Drivetrain (FWD, RWD, AWD)",
                "explanation": "The 'drivetrain' is all the parts that send the engine's power to the *driving wheels*.\n\n• **FWD (Front-Wheel Drive)**: The engine, transmission, and driving wheels are all at the front. Most common, good in snow.\n• **RWD (Rear-Wheel Drive)**: The engine is at the front, but a long 'drivetrain' sends power to the rear wheels. (Common in trucks & sports cars).\n• **AWD (All-Wheel Drive)**: A complex 'transfer case' and 'differentials' send power to all four wheels.",
                "example": "FWD: The car is 'pulled'.\nRWD: The car is 'pushed'.\nAWD: The car is 'pulled' and 'pushed'."
            },
            {
                "title": "The Differential",
                "explanation": "This is a clever set of gears, located between the two driving wheels. When you turn a corner, the *outside* wheel must spin *faster* than the *inside* wheel. The differential allows this to happen, splitting the engine's power so each wheel can rotate at a different speed while still providing power.",
                "example": "Key Idea:\nWithout a differential, when turning, one wheel would have to 'skip' or 'drag' along the pavement, causing a loss of control."
            }
        ]
    },
    {
        "groupTitle": "Section 4: Brakes, Steering & Suspension",
        "topics": [
            {
                "title": "Brake System (Hydraulics)",
                "explanation": "Brakes don't use wires or rods; they use 'hydraulics' (fluid pressure). When you push the brake pedal, you are pushing a piston in the 'master cylinder'. This pressurizes brake fluid in a sealed system of hoses. This pressure is sent to all four wheels, where it forces 'calipers' (or 'wheel cylinders') to clamp down.",
                "example": "Key Idea:\nFluid cannot be compressed. Pushing fluid in one place (the pedal) makes it push *equally* hard in another place (the wheels). This multiplies your foot's force."
            },
            {
                "title": "Disc Brakes (Pads & Rotors)",
                "explanation": "The most common type of brake. This system works like a bicycle's hand brake.\n\n• **Rotor**: A heavy metal disc that spins *with* the wheel.\n• **Caliper**: A C-shaped clamp that sits *over* the rotor.\n• **Brake Pads**: Two pieces of high-friction material inside the caliper. When you brake, the caliper squeezes the pads against the spinning rotor, stopping the car with friction.",
                "example": "Common Maintenance:\nBrake pads are designed to wear down and be replaced. The 'squealing' sound is often a small metal tab on the pad, called a 'wear indicator', telling you it's time for a change."
            },
            {
                "title": "Drum Brakes",
                "explanation": "An older style of brake, now mostly found on the *rear* wheels of cheaper cars. Instead of a disc, it uses a hollow 'drum' that spins with the wheel. Inside the drum are two 'brake shoes' that, when you brake, are forced *outward* to press against the inside of the spinning drum, creating friction.",
                "example": "Disc vs. Drum\n- Disc Brakes: Clamp *inward* on a disc.\n- Drum Brakes: Push *outward* inside a drum."
            },
            {
                "title": "Suspension System",
                "explanation": "The suspension system connects the wheels to the body of the car and has two jobs:\n1. **Comfort**: Absorb bumps in the road using 'springs' (either coil springs or leaf springs).\n2. **Control**: Control the bouncing of the springs using 'shock absorbers' (or 'struts').",
                "example": "Springs vs. Shocks:\n• The **Spring** holds the car up and absorbs a bump.\n• The **Shock Absorber** stops the spring from bouncing up and down over and over. A car with 'bad shocks' will feel very 'bouncy' after a bump."
            },
            {
                "title": "Steering System",
                "explanation": "The 'steering' is how the steering wheel turns the front wheels. In modern cars, it's a 'Rack and Pinion' system.\n\n• **Rack**: A long, flat bar with teeth, connected to the wheels.\n• **Pinion**: A small gear, connected to your steering wheel.\n\nWhen you turn the wheel, the pinion gear moves along the rack, pushing the wheels left or right.",
                "example": "Power Steering:\nThis system is 'assisted' by a pump (hydraulic or electric) that helps you move the rack, making it easy to turn the wheel, especially at low speeds."
            },
            {
                "title": "Tires",
                "explanation": "Tires are the single most important safety feature, as they are the *only* part of the car that touches the road. The 'tread' is a pattern of grooves designed to channel water away from the 'contact patch' (the part touching the ground) to prevent 'hydroplaning' (skidding on water).",
                "example": "Tire Codes:\nP215/65R15\n• **215**: Width of the tire (mm)\n• **65**: Aspect ratio (sidewall height as % of width)\n• **R**: Radial (the type of construction)\n• **15**: Diameter of the wheel (inches)"
            }
        ]
    },
    {
        "groupTitle": "Section 5: Basic Maintenance",
        "topics": [
            {
                "title": "How to Change Your Oil",
                "explanation": "This is the most basic and important DIY task. The process is:\n1. Warm up the engine (to make the oil flow).\n2. Safely raise the car (use ramps or jack stands).\n3. Place a pan underneath and remove the 'drain plug' (a bolt on the bottom) to drain the old oil.\n4. Remove the old oil filter.\n5. Replace the drain plug and install a new, lubricated filter.\n6. Fill the engine with the correct amount and type of new oil.",
                "example": "Key Tools:\n- Wrench (for drain plug)\n- Oil filter wrench\n- Drain pan\n- Funnel\n- Jack stands or ramps"
            }
        ]
    }
]