Common Causes of Car Fires and Complete Emergency Extinguishing Process with Fiberglass Fire Blankets

Introduction

A car fire rarely starts without warning. There's almost always something that came before it — a smell, a sound, a dashboard warning light, a stain on the driveway. Most drivers either don't notice these signs or don't know what they mean. By the time flames are visible, the window for early-stage intervention is already closing.

Understanding why vehicle fires start — and what they look like in the minutes before they fully ignite — changes how you respond. And knowing the correct process for using a fiberglass fire blanket means that when the moment arrives, you're not figuring it out from scratch.

This guide covers the six most common causes of car fires, the early warning signs that precede them, and a step-by-step suppression process matched to each cause type.

Six Common Causes of Car Fires

Vehicle fires don't all start the same way. Each cause produces a different type of fire, in a different location, with different suppression requirements. Knowing the cause changes how you respond.

Fuel system leaks are the most frequent cause. A cracked fuel line, a loose connection, or a leaking fuel injector deposits petrol or diesel onto hot engine surfaces — where ignition is almost immediate.

Electrical faults are the second most common — and the most unpredictable. A short circuit in ageing wiring, a faulty aftermarket accessory, or water damage to an electrical system can start a fire in any location connected to the vehicle's electrical network.

Engine overheating — particularly from coolant loss or a failed water pump — leads to oil reaching ignition temperature and catching on hot metal surfaces.

EV battery failures — from collision damage, overcharging, or manufacturing defects — trigger thermal runaway in lithium-ion cells. This is self-sustaining combustion that generates its own oxygen and cannot be extinguished by conventional means alone. The right tool here is an EV battery fire blanket used for containment.

Catalytic converter heat is an underappreciated cause. Converters operate at 400–900°C during normal use. Parking over dry grass or leaves can ignite the vegetation underneath. It starts as a ground fire and climbs.

Flammable cargo in the boot — aerosol cans, fuel containers, cleaning products — can ignite from heat alone on a hot day or from a spark source nearby.

The difference between a contained emergency and a total loss is often just a few minutes. These are the signals that come before the flames.

Burning smell without visible smoke — particularly a sharp chemical or rubber smell — almost always means something is overheating. Don't ignore it. Pull over.

Dashboard warning lights — engine temperature warning, battery warning, or oil pressure light — are the vehicle telling you something is wrong. They are not suggestions. A temperature gauge that's been in the red for more than a minute means the engine is already in dangerous territory.

Smoke from under the bonnet — even thin, light-coloured smoke — means heat is reaching something it shouldn't. White smoke is usually coolant burning off. Black smoke often means oil or fuel. Either warrants stopping immediately.

Fluid puddles under the car — after parking, a coloured puddle (dark brown for oil, clear/green for coolant, colourless/petrol-smelling for fuel) indicates a leak that will eventually find an ignition source.

Flickering interior electrics — lights, radio, or dashboard items behaving erratically can indicate a wiring fault in progress. This is particularly true in older vehicles with degraded insulation.

The broad deployment process for a car fire blanket is the same regardless of cause — but there are important variations depending on where and why the fire started.

Engine bay fire (fuel/oil/electrical): Do not open the bonnet. Retrieve the blanket, shake it fully open, and lower it over the entire front of the vehicle from the windward side. Seal edges to the ground. Wait 20–30 minutes minimum. Call emergency services.

EV battery fire: Keep all doors and the bonnet closed — do not introduce oxygen. Deploy the blanket over the full vehicle floor area — not just the front. EV battery fires need full-vehicle coverage because the heat source is under the entire floor. Wait longer than you would for a petrol fire — 30 minutes minimum — before considering the situation stable. Re-ignition risk is higher and can occur hours later.

Boot / cargo fire: If accessible from outside and fire is contained to the boot, deploy the blanket over the rear of the vehicle and seal to the ground. If the boot is already fully involved, don't open it — deploy over the entire vehicle.

Catalytic converter / undercarriage fire: If the ground underneath is burning, the priority is getting the vehicle away from the fuel source if safe to do so. Then deploy the blanket over the vehicle as normal.

For a full breakdown of suppression techniques by scenario, this article is useful: Selection & Correct Use of Fiberglass Fire Blankets for Different High-Risk Scenarios.

When Not to Use a Fire Blanket — Escape Guide

A fiberglass blanket is a first-response tool for early-stage fires. There are situations where using it is not the right call.

If the fire has reached the fuel tank — flames coming from the undercarriage near the rear of the vehicle, or a visible fuel fire underneath — evacuate immediately. Get at least 30 metres away. The risk of fuel tank rupture makes proximity dangerous.

If the passenger compartment is involved — fire inside the cabin means trapped occupants are the priority, not suppression. Use the blanket as a personal shield if needed during evacuation assistance, not as a suppression tool.

If the vehicle is in an enclosed space with no ventilation — toxic gases from burning materials accumulate rapidly in underground carparks and garages. Suppression takes second place to evacuation.

If you're alone and the fire is already fully developed — a single person cannot safely deploy a large blanket over a fully burning vehicle. Don't attempt it. Call emergency services and move away.

The rule is simple: the blanket is for early-stage containment. If you've missed that window, your job is to get away and let professionals handle the rest. For further reading on core suppression principles, this article covers the fundamentals well: Emergency Fire Suppression of Small-Scale Fires: The Core Role of Fiberglass Fire Blankets.

Summary

Car fires follow patterns — predictable causes, recognisable warning signs, and defined suppression windows. The six causes outlined here account for the vast majority of vehicle fire incidents. Knowing them changes how you monitor your vehicle and how quickly you respond when something doesn't seem right.

A fiberglass car fire blanket is most effective in the first two to three minutes of a fire event. After that, the options narrow. Keep the blanket accessible, know the deployment process for your specific vehicle type, and understand where the line is between first-response and full evacuation.

Questions on which product suits your vehicle and use case? The INSOFIRE FAQ covers the most common queries.

About INSOFIRE

INSOFIRE — InsoFire Material Technology Hangzhou Co., Ltd. — has been producing fiberglass-based fire protection products since 1993. With over 30 years of manufacturing expertise and a 33,000 m² production facility, the company supplies car fire blankets, standard fire blankets, e-bike fire blankets, and custom fireproof solutions for automotive, industrial, and commercial clients globally. Products meet ISO, EN, ASTM, and AS/NZS standards. OEM and ODM production available. Contact: sales@insofire.com or browse the complete product catalog.