Why Cars Usually Catch on Fire

Cars most often catch fire when heat from engines or electrics meets flammable materials—typically leaked fuel or oil, overheated exhaust components, or faulty wiring. Collisions that rupture tanks or batteries, neglected maintenance, and, more rarely, battery thermal runaway in electric vehicles are the leading pathways that turn small faults into fires.

How vehicle fires start

Any car fire needs three elements: fuel, heat, and oxygen. Vehicles carry multiple fuels—gasoline, diesel, engine oil, transmission fluid, brake fluid, and, in the case of EVs, stored electrical energy—while engines, exhaust parts, and batteries supply heat. When a leak, fault, or crash brings these together, ignition can follow.

Internal combustion vehicles

In gasoline and diesel cars, fires most often begin in the engine or exhaust area. Hot surfaces (manifolds, catalytic converters, turbo housings) can exceed hundreds of degrees Celsius. If combustible fluids drip or spray onto these parts—or if electrical arcs occur in worn wiring—flames can start and spread along plastic shrouds, hoses, and insulation.

Electric vehicles

EVs rarely ignite, but when they do the cause is usually battery-related damage or defects leading to thermal runaway—an uncontrollable heat buildup inside cells. Triggers include severe crashes, internal cell faults, manufacturing defects, water intrusion (especially saltwater), or improper repairs. EV fires behave differently, can re-ignite, and may require extended cooling, but they remain uncommon relative to the growing fleet.

The most common ignition sources

The following list outlines the typical technical pathways that start vehicle fires, based on fire service investigations and automotive failure patterns.

• Fuel system leaks: Cracked hoses, corroded lines, loose injector seals, or failed fuel rails spray gasoline or diesel onto hot engine parts.
• Oil and fluid leaks: Engine oil, transmission fluid, power steering fluid, and brake fluid can ignite on exhaust components or catalytic converters.
• Electrical faults: Chafed wiring, short circuits, overloaded circuits from aftermarket accessories, failing alternators, and bypassed fuses create sparks and overheated conductors.
• Overheating exhaust/catalytic converters: A clogged or failing catalytic converter runs extremely hot and can ignite nearby materials or roadside grass under a parked vehicle.
• Mechanical friction: Seized wheel bearings, dragging brakes, or stuck parking brakes generate enough heat to ignite tires or brake components.
• Collisions: Impacts rupture fuel systems in ICE vehicles or damage high-voltage packs in EVs and hybrids, releasing fuel or causing internal shorting.
• Poor maintenance and recalls ignored: Degraded hoses, old wiring, oil leaks, and unresolved recall defects increase fire risk over time.
• Aftermarket modifications: Improperly installed audio systems, remote starters, performance parts, or non-OEM batteries can overload circuits or reroute heat and airflow.
• External ignition: Arson, wildfires, or parking over dry vegetation that contacts a hot exhaust.

While any of these can ignite a vehicle, most fires follow a chain: a small, preventable fault (leak or wiring issue) meets a heat source, then spreads through plastics and interior materials.

Circumstances that raise risk

Some environments and conditions make ignition and fire spread more likely, even for well-designed vehicles.

• Age and mileage: Older vehicles with worn seals, cracked insulation, and corrosion are overrepresented in fire statistics.
• Heavy loads and high ambient heat: Towing, mountain grades, and heat waves strain cooling systems and exhaust components.
• Stop-and-go driving with poor airflow: Underhood temperatures rise, exacerbating small leaks and electrical hot spots.
• Road salt and flooding: Corrosion accelerates on fuel and brake lines; water intrusion can compromise wiring and EV battery packs after severe exposure.
• Recent repairs: Misrouted hoses, loose clamps, spilled fluids, or unprotected wiring after service can create immediate hazards.
• Parking over dry vegetation: A hot catalytic converter can ignite grass in under a minute.

Understanding these contexts helps drivers time inspections and adjust driving and parking habits to lower the chance of a small issue turning into a fire.

Warning signs drivers should not ignore

Early detection often prevents a fire. These symptoms warrant immediate attention and, if present while driving, a safe pull-over and engine shutdown.

• Smell of gasoline or a sweet, burnt, or acrid odor (oil, coolant, electrical insulation).
• Visible smoke from wheel wells, vents, or under the hood; or unusually hot hood/floorboards.
• Sudden electrical anomalies: flickering lights, burning-plastic smell, or repeatedly blowing fuses.
• Warning lights with overheating: temperature or battery/charging warnings, reduced power, or misfires.
• Fluid drips under the car that look oily, rainbow-colored, or smell of fuel.
• Dragging sensation, brake smoke, or a wheel too hot to touch (possible brake or bearing issue).

Promptly responding to these clues—by stopping in a safe place, shutting off the engine, and calling for assistance—can stop escalation.

Prevention: practical steps that work

Routine maintenance and careful modifications are the most effective fire prevention tools for any vehicle type.

1. Fix leaks immediately: Inspect and replace aging fuel lines, injector seals, valve cover gaskets, and transmission or power steering hoses.
2. Respect electrical design: Avoid overloading circuits; use proper fuses; route wires with abrasion protection; choose professional installation for accessories.
3. Keep the engine bay clean: Remove oil residue and debris; ensure heat shields and splash guards are intact.
4. Monitor exhaust health: Address catalytic converter and exhaust restrictions; resolve persistent misfires that overheat the catalyst.
5. Service brakes and bearings: Investigate pulling, noise, or heat; ensure calipers slide freely and parking brakes release fully.
6. Check for and complete recalls: Use your VIN to verify open recalls and get dealer fixes at no cost.
7. Be EV-smart: After a crash, flooding, or underbody strike, have high-voltage systems inspected; follow manufacturer guidance on charging and storage.
8. Park wisely: Avoid dry vegetation; in garages, leave space around the vehicle and keep combustibles away.

These measures reduce both the chance of ignition and the severity of any incident, often at modest cost during regular service intervals.

If your vehicle catches fire: what to do

Safety comes first. The steps below reflect fire service guidance for drivers facing smoke or flames.

1. Signal and pull over immediately to a safe area, away from traffic and buildings; stop and shift to park.
2. Shut off the engine and, for EVs/hybrids, power down fully; do not open the hood if flames are present (air feeds fire).
3. Evacuate everyone, move at least 100 feet (30 meters) upwind, and keep bystanders back.
4. Call emergency services; report if it’s an EV/hybrid so responders can plan for high-voltage hazards.
5. Use a fire extinguisher only on very small, early-stage fires, from a safe distance, and only if you have a clear escape path.
6. Do not return to the vehicle for belongings; for EVs, be aware of possible re-ignition and follow responders’ instructions.

Quick, calm actions minimize risk to people and property—vehicles are replaceable, lives are not.

What the data show

Fire service and safety agencies consistently report that mechanical or electrical failure is the leading factor in highway vehicle fires, and most begin in the engine or running-gear area. Collisions account for a smaller share of incidents but a disproportionate share of fatalities. Older, higher-mileage gasoline vehicles dominate the statistics because they vastly outnumber EVs and because age and wear increase risk. Emerging fleet-adjusted analyses from several countries indicate that EVs ignite at rates comparable to or lower than internal-combustion vehicles, though EV fires require different tactics and can be more persistent once started. As the vehicle mix evolves, agencies continue to refine guidance, but the core prevention message—fix leaks, maintain electrical integrity, and complete recalls—remains constant.

Summary

Cars usually catch fire when a preventable fault—most often a fuel or oil leak, an electrical short, or overheated exhaust components—meets abundant heat under the hood or along the exhaust path, sometimes after a crash. Good maintenance, careful wiring, prompt leak repairs, and attention to warning signs dramatically cut risk for both gasoline and electric vehicles, while smart actions during an incident keep people safe if a fire does occur.

Why would a car get caught on fire?

Usually cars catch fire due to the exposure of flammable liquids (such as gasoline) to surfaces hot enough to ignite them. This might be the exterior of a running engine, especially one which is damaged, or simply the sparks produced by forceful contact between steel or iron within a collision.

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.

Is it rare for a car to catch on fire?

No, car fires are not considered rare; the National Fire Protection Association (NFPA) estimates nearly 300,000 vehicle fires occur each year in the U.S., though the overall risk is low compared to the total number of vehicles on the road. While the number of incidents is down from peak years, there has been a recent uptick in both incidents and associated fatalities. 
Statistics on Vehicle Fires

• Frequency: Roughly 300,000 vehicle fires are estimated to happen each year in the U.S. 
• Risk: Despite the number, the risk per vehicle is low, with approximately 0.04% of registered vehicles catching fire annually. 
• Recent Trends: While the overall number of vehicle fires has decreased since 2005, there has been an increase in incidents and civilian deaths in recent years. 

Common Causes

• Mechanical Failure: A significant cause, often related to engine oil leaks or worn-out components. 
• Electrical Failure: Issues with a vehicle’s wiring or electrical systems can lead to fires. 
• Accidents: Crashes can rupture fuel lines or tanks, leading to fires. 
• Lack of Maintenance: Neglecting maintenance can cause rubber hoses and seals to fail, leading to fluid leaks and potential fires. 
• Flammable Materials: Improper storage of flammable materials, like rags or paper towels, under the hood can ignite. 

Key Takeaways

• Significant Risk: Although not common for a single driver, car fires are a significant risk, contributing to deaths and injuries each year. 
• Prevention: Proper maintenance, addressing recalls, and avoiding the buildup of flammable materials are key ways to prevent fires. 
• Increased Danger: Car fires can escalate rapidly, posing a severe threat to occupants and those nearby. 

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.