Where Do Most Fires Start in a Car?

Most car fires start in the engine compartment—often including the engine, running gear, or wheel/brake area—driven primarily by mechanical failures, electrical faults, fluid leaks, and heat from components like catalytic converters. Data analyses by fire safety organizations in recent years consistently show that roughly three out of five highway vehicle fires begin in or near the engine bay, while a smaller share start in passenger cabins or cargo areas; for electric vehicles, fires most often originate in the high-voltage battery pack, though such incidents remain far less common overall than engine-bay fires in conventional cars.

What the Data Show

Fire incident data compiled by U.S. fire safety groups over multiple study periods indicate a clear pattern: the engine area is the leading “area of origin” for highway vehicle fires. In aggregated NFPA analyses, approximately 60% or more of on-road vehicle fires start in the engine compartment, running gear, or wheel area. Mechanical failure and electrical malfunction are the dominant contributing factors, with combustible fluids (oil, fuel, power steering fluid) and high-heat components increasing ignition risk. Passenger compartments, trunks, and cargo areas account for a smaller share of starts in most datasets.

Why the Engine Bay Dominates

The engine compartment concentrates heat, moving parts, electrical circuits, and flammable fluids in a tight space. The following points outline why it is the most common origin of vehicle fires.

• Heat concentration: Engines, exhaust manifolds, turbochargers, and catalytic converters operate at high temperatures, easily igniting leaked fluids or debris.
• Flammable fluids: Fuel, oil, transmission and power steering fluids can leak onto hot surfaces or wiring.
• Electrical complexity: Alternators, starters, wiring harnesses, and aftermarket accessories add failure points for shorts and overheating.
• Vibration and wear: Road shock and age can chafe hoses and insulation, loosening connections over time.
• Airflow: The engine bay’s airflow can feed and spread flames once ignition occurs.

Taken together, these conditions create multiple ignition pathways—especially as vehicles age or maintenance is deferred—making the engine bay the statistical hotspot for fire starts.

Differences by Powertrain: Gas/Diesel vs. Hybrid/EV

Powertrain type influences the most likely ignition source and how a fire develops.

• Gasoline and diesel vehicles: Most starts occur in the engine, wheel/brake, or exhaust area. Fuel leaks, oil seeping onto hot parts, worn wiring, seized brakes, or overheated catalytic converters are frequent triggers.
• Hybrids: Combine traditional engine-bay risks with high-voltage systems. Faults can involve both 12V and high-voltage components; cooling issues in battery packs or power electronics can contribute.
• Battery-electric vehicles (EVs): When EV fires occur, the origin is often the traction battery due to thermal runaway from internal cell defects, impact damage, or charging faults. However, EV fire incidence remains low relative to the overall fleet, and EVs also have conventional 12V circuits that can fail.

While the power source changes the likely ignition point, good design, robust battery management, and proper maintenance reduce risk across all vehicle types.

Other Common Points of Origin

Beyond the engine bay, several areas routinely appear in incident reports as secondary hotspots for vehicle fire starts.

• Wheel/brake assemblies: Dragging brakes, stuck calipers, or overheated pads can ignite grease, dust, or nearby components.
• Exhaust and catalytic converter area: Hot exhausts can ignite dry grass or road debris trapped under the car.
• Passenger cabin: Faulty wiring to infotainment, seat heaters, or aftermarket devices; smoking materials; or portable battery packs can start interior fires.
• Cargo/trunk: Improperly stored fuel cans, aerosols, or lithium batteries can ignite, especially in hot weather.
• Undercarriage: Fluid leaks onto hot components or damaged wiring from road debris can cause ignition underneath the vehicle.

While less frequent than engine-bay starts, these areas underscore that heat, electricity, fuel, and combustible materials can intersect in many parts of a vehicle.

Early Warning Signs

Recognizing early indicators can prevent a small problem from becoming a fire.

• Sharp, acrid electrical smell; visible smoke wisps from vents or the engine bay.
• Burning oil, fuel, or “hot plastic” odors after driving or charging.
• Dashboard warnings for battery/charging, temperature, or alternator; dimming lights or flickering electronics.
• Fluid spots under the car; sudden drop in oil or coolant levels.
• Brake drag, strong burning smell from a wheel, or the vehicle pulling to one side.

If you detect these signs, pull over safely, shut the vehicle off, and call for assistance before opening the hood, which can add oxygen and intensify a smolder.

Prevention Tips

Routine maintenance and sensible habits dramatically reduce fire risk.

• Keep up on maintenance: Replace frayed belts/hoses, fix leaks promptly, and address check-engine or charging warnings.
• Inspect wiring: Look for chafing or corrosion; use proper fusing and quality parts for any aftermarket installs.
• Mind heat sources: Clear debris from the undercarriage; don’t park over tall dry grass with a hot exhaust.
• Brake health: Service brakes regularly; address dragging or vibration immediately.
• Battery care: For EVs/hybrids, follow charging guidelines; avoid impact to the underbody; for all cars, secure the 12V battery and terminals.
• Safe storage: Keep fuel cans, aerosols, and lithium batteries out of hot cabins and away from direct sun.
• Carry basics: A compact, automotive-rated fire extinguisher (e.g., dry chemical or clean agent) can help with very small, early-stage fires.

These steps target the most common ignition pathways and help contain minor issues before they escalate.

What To Do If You Suspect a Fire

If you think a fire may be starting, act quickly and prioritize safety.

1. Signal, pull over safely, and stop the vehicle; shift to park and turn off the engine (or high-voltage system in EVs).
2. Evacuate all occupants immediately and move at least 100 feet (30 meters) away and uphill if possible.
3. Do not open the hood if smoke is visible; introducing oxygen can intensify flames.
4. Call emergency services. Provide location, vehicle type (gas/diesel/hybrid/EV), and what you observe.
5. Use a fire extinguisher only on small, incipient fires from a safe distance; if in doubt, stay clear.

Rapid evacuation and professional response are your safest options; vehicles can flash over quickly and release toxic fumes.

Summary

Most vehicle fires start in the engine compartment—including the engine, running gear, or wheel/brake area—because that’s where heat, flammable fluids, and complex wiring converge. While EV-specific incidents tend to originate in traction batteries, overall highway vehicle fire data still point overwhelmingly to engine-bay origins in the broader fleet. Watch for smells, smoke, warnings, and leaks; maintain brakes, wiring, and fluids; keep debris away from hot exhausts; and act quickly if a fire is suspected.

What part of a car is most likely to catch fire?

1: Fuel System Leaks. Leaks in the fuel system are the most common cause of vehicle fires, so that’s why they take the top spot on our list. A fuel system leak is really dangerous.

What is the most common cause of car fires?

The most common causes of car fires are fuel system leaks, where flammable liquids ignite from a spark or hot engine component, and electrical system failures, which can cause sparks from faulty wiring or components. Poor vehicle maintenance can lead to both of these issues, increasing the risk of a fire from damaged wires or leaking components. 
Causes of Car Fires

• Fuel System Leaks: Flammable liquids like gasoline can leak from damaged lines or components and contact a hot engine part or a spark, leading to ignition. 
• Electrical System Failures: Worn or damaged wiring, short circuits, or faulty components can create sparks or heat, igniting nearby materials. 
• Poor Maintenance: Neglecting regular maintenance can result in damaged electrical wires, leaky fuel lines, or engines that overheat, all of which are fire hazards. 
• Engine Overheating: Overheating can cause fluids to spill and come into contact with hot engine components or wires. 
• Car Accidents: A collision can cause damage to the fuel tank, fuel lines, or electrical systems, leading to leaks, sparks, and potential ignition of flammable liquids. 
• Catalytic Converter Issues: A damaged or improperly functioning catalytic converter can become extremely hot and pose a fire risk if it contacts foreign objects. 

Prevention

• Perform Regular Maintenance: Have your car inspected and serviced regularly to catch potential problems with the fuel and electrical systems. 
• Be Vigilant for Leaks: If you smell gasoline or see fluid leaks under your car, get it checked and fixed immediately. 
• Address Electrical Issues: Don’t ignore warning signs of electrical problems, such as flickering lights or other malfunctions. 

Where do car fires usually start?

Fuel leaks are a top cause of car fires because gasoline is incredibly flammable and can quickly start a fire in the vehicle. Electrical system failure: All cars have an electrical system that runs throughout the vehicle, including in the hood, doors, and through the powered seats.

Where do vehicle fires generally start?

Most vehicle fires start in the engine compartment, running gear, or wheel area due to mechanical issues like fuel system leaks, electrical system failures, or overheating components. A fuel system leak is particularly dangerous as it introduces highly flammable gasoline into an area with potential ignition sources, like a spark or hot engine part.
 
Common starting points for vehicle fires:

• Engine Compartment: This is the most common area for a fire to begin, often caused by: 
  • Fuel Leaks: Leaks in fuel lines, hoses, or connections can release flammable gasoline that can easily ignite from a spark or heat source. 
  • Electrical Failures: Faulty wiring, short circuits, or other electrical system malfunctions can generate sparks, igniting nearby flammable materials or fluids. 
  • Overheating Components: Parts like the catalytic converter can get extremely hot and ignite road debris or other combustible materials that accumulate around them. 
• Running Gear and Wheel Area: Fires can also start in these areas due to:
  • Mechanical Failures: Problems with the drivetrain, bearings, or other moving parts can create excessive heat. 
  • Road Debris: Debris can get caught on the undercarriage and ignite from heat or friction. 
  • Electrical Issues: Wiring in the wheel wells or near the axles can also fail and spark. 

Why these areas are so prone to fires:

• Proximity to Ignition Sources: The engine compartment is a complex area with many hot components (engine, exhaust) and electrical systems, creating numerous potential ignition points. 
• Presence of Flammable Materials: Cars contain highly flammable liquids like gasoline, oil, and coolant, which can easily ignite if leaked and exposed to heat or sparks. 
• Concentration of Components: The dense arrangement of parts in the engine and running gear makes fire spread rapidly.