What Is the Most Common Cause of Car Fires?

The most common cause of car fires is mechanical failure or malfunction, especially in the engine compartment, according to recent analyses of U.S. highway vehicle fires by fire agencies such as the National Fire Protection Association (NFPA). While electrical faults also rank highly and crashes are a leading factor in fatal fires, routine, non-crash fires most often begin with heat, fuel, or fluid issues tied to mechanical problems under the hood.

Where and How Car Fires Typically Start

Most vehicle fires start in the engine, running gear, or wheel area—places where combustible fluids, hot surfaces, and moving parts converge. Heat from engines and catalytic converters, combined with leaking fuel or oil and aging components, creates conditions ripe for ignition. Although electric vehicles (EVs) introduce different hazards—namely battery thermal runaway—traditional gasoline and diesel cars still account for the overwhelming majority of vehicle fires, and their leading triggers remain mechanical in nature.

The Leading Causes, Explained

The factors below reflect patterns consistently seen in fire incident data. Understanding them helps drivers prioritize maintenance and reduce risk.

• Mechanical failure or malfunction: The top driver of car fires, often involving fuel or oil leaks, overheated engines, seized bearings, or catalytic converters igniting nearby materials. Worn hoses, cracked fuel lines, and degraded seals are frequent culprits.
• Electrical system failure: Short circuits, damaged wiring harnesses, overloaded add-on accessories, faulty alternators, or battery issues can arc and ignite plastics and insulation. In EVs and hybrids, high-voltage components require specialized safeguards, though these fires remain a smaller share overall.
• Crashes and rollovers: Collisions can rupture fuel systems, damage electricals, and expose hot surfaces, causing some of the most severe and deadly fires—even if they constitute a smaller percentage of total incidents.
• Intentional or incendiary causes: Arson and insurance fraud represent a notable subset; these vary with local patterns and enforcement.
• Poor maintenance or unsafe modifications: Deferred repairs, incorrect fuses, substandard aftermarket parts, and improper installations can compound both mechanical and electrical risks.

Taken together, these causes show why engine-bay upkeep is critical: preventing leaks, managing heat, and protecting wiring substantially lowers the likelihood of a fire.

Warning Signs That Raise Fire Risk

Early detection can prevent a breakdown from becoming an emergency. Watch for the following symptoms and address them promptly.

• Smell of gasoline, burning oil, or melting plastic.
• Visible fluid leaks under the vehicle or on engine components.
• Engine overheating, temperature warning lights, or steam from the hood.
• Electrical gremlins: flickering lights, repeatedly blown fuses, or hot-to-the-touch wiring/connectors.
• Warning indicators: battery/charging light, check engine light, or hybrid/EV system alerts.
• Unusual exhaust heat: glowing catalytic converter or heat shimmering under the car.
• Misfires, loss of power, or rough running—often linked to heat and fuel delivery issues.

Addressing these red flags—especially leaks and overheating—dramatically reduces the chance of a small fault escalating into a fire.

How to Reduce Your Risk

Preventive maintenance and smart operating habits are the most effective tools for avoiding a fire. The steps below focus on the highest-impact actions.

• Fix fluid leaks immediately and replace aging fuel, oil, and coolant hoses and clamps.
• Service the cooling system and ensure fans, belts, and thermostats function properly to prevent overheating.
• Keep the engine bay clean of oil and debris; residues can ignite on hot surfaces.
• Protect the electrical system: repair frayed wires, use correct fuses, and avoid overloading circuits with aftermarket accessories.
• Check for and complete safety recalls promptly—especially fuel system, electrical, and battery-related campaigns.
• Avoid parking over dry grass; catalytic converters can ignite vegetation.
• Refuel safely: shut off the engine, don’t smoke, and wipe any spilled fuel.
• For EVs and hybrids: use manufacturer-approved chargers, avoid damaged cables, and park/charge away from combustible clutter if a battery issue is suspected.
• Carry a compact A-B-C or B-C rated extinguisher and know how to use it—but prioritize evacuation over firefighting.

These precautions target the most common ignition pathways—heat, fuel, and faulty wiring—offering strong risk reduction for minimal cost and effort.

What To Do If Your Car Catches Fire

Quick, calm actions can save lives. If you suspect a fire—smoke, flames, or a pungent burning smell—follow these steps.

1. Signal and pull over safely; stop, shift to park, and set the parking brake.
2. Turn off the engine and electrical systems to cut fuel and power sources.
3. Evacuate everyone immediately; move at least 100 feet upwind and uphill if possible.
4. Call emergency services and give your exact location; mention if it’s an EV or hybrid.
5. Do not open the hood or trunk—introducing oxygen can intensify the fire.
6. Warn oncoming traffic from a safe distance; keep bystanders away.
7. Use an extinguisher only if the fire is very small, no flames are visible from the engine bay, and you have a clear escape route.
8. Do not re-enter the vehicle. For EVs/hybrids, be aware of potential re-ignition; follow responders’ guidance.

Personal safety comes first. Vehicles are replaceable; attempting to fight a growing fire is rarely worth the risk.

Methodology and Context

This assessment reflects patterns reported by U.S. fire agencies and NFPA analyses of highway vehicle fires in recent years. The term “most common cause” refers to leading factors contributing to ignition across non-crash vehicle fires, where mechanical failure or malfunction predominates. Electrical failures are typically the second most frequent cause. Crashes remain a major factor in fatal fires due to the severity of damage. Regional variations and fleet composition can shift local patterns, but the national picture remains consistent as of 2025.

Summary

Mechanical failure or malfunction—particularly in the engine compartment—is the most common cause of car fires. Electrical faults are also significant, while crashes account for many of the deadliest incidents. Staying on top of leaks, heat management, and wiring integrity, combined with prudent refueling and charging practices, offers the best protection against vehicle fires.

What is the biggest 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 most vehicle fires 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. 

How do car fires normally start?

Some common causes of fires include: Ignition of flammable liquids. The leading cause of vehicle fires occurs when flammable liquids such as gasoline and oil accidentally ignite from a spark, an overheated engine, or a hot exhaust. Fume ignition.

What cars are most likely to catch fire?

Hybrid vehicles currently have the highest rate of fires, with gasoline-powered cars second and electric vehicles (EVs) being the least prone to fires. Among specific models, Kias and Hyundais have a significant history of engine and electrical fires due to shared parts, while some high-end electric models like the Jaguar I-Pace have also faced fire recalls for battery issues. 
By Vehicle Type: 

• Hybrids: Opens in new tabThese vehicles have the highest reported fire rate, at approximately 3,475.5 fires per 100,000 vehicles sold.
• Gasoline Cars: Opens in new tabThese are the second most likely to catch fire, with a rate of 1,529.9 fires per 100,000 vehicles sold.
• Electric Vehicles (EVs): Opens in new tabEVs have the lowest fire risk, with a rate of just 25.1 fires per 100,000 vehicles sold.

By Manufacturer/Model:

• Kias and Hyundais: These brands have a high risk due to shared parts leading to issues like engine oil leaks, faulty rod bearings, and electrical shorts. Recalls have affected millions of vehicles. 
• Specific Hybrid Models: The Hyundai Tucson and Sonata hybrids have been recalled due to issues that could cause engine fires. 
• Electric Models with Issues: The Jaguar I-Pace has had a high number of recalls for battery overheating, which can lead to fires, and owners are advised to park the vehicle away from structures. 
• Historical Examples: The Ford Pinto is infamous for a design flaw that caused its gas tank to rupture and cause fires in collisions. 

Why Hybrids are More Prone to Fires:

• The combination of a traditional gasoline engine, an electric battery, and the complex systems that manage both can lead to more potential points of failure. 
• While the exact reasons are still being studied, the high-voltage systems and the overlap of gasoline and electric components are believed to contribute to the elevated risk, according to a YouTube video.