Car Fires: Causes, Prevention and What to Do
by Terry Buis
Owner Sun Valley Automotive
Las Vegas Auto Repair
4553 N. Rancho Dr. Las Vegas, Nevada 89130
Risks for car fires can be higher in the desert climate, but all vehicle owners should be aware of the risks of vehicle fires plus how to prevent them. Find out everything you need to know, including what to do if your car catches on fire, with this Terry’s Tip – written personally by Terry Buis, owner of Sun Valley Automotive, Las Vegas auto repair.
In our desert climate, we’re not the only ones feeling the effects of this hot dry environment. Our vehicles are beat from the heat too. Seals dry up at a much faster rate than the rest of the country, hoses can dry rot and all vehicle parts are exposed to higher extreme temperatures.
The good news? Even though drivers in Nevada can have higher risks for car fires, a lot of these risks can be reduced with automotive maintenance.
How do Car Fires Start?
Three things are needed to make a fire: Oxygen, Fuel and an Ignition Source.
Car fires are usually related to causes associated with fuel, electrical systems, the exhaust system and petroleum based fluids.
By far though, the biggest causes of vehicle fires are fuel (gasoline) related.
1. Fuel Related Car Fires
Vehicle fires in these cases start, for the most part, at the fuel rail where we find the fuel injectors and fuel pressure regulators. These two components have O-rings that wear out with time and from dry heat.
Fuel injectors and fuel pressure regulators are under pressure – once a cracked or broken O-ring starts leaking while a car is running, a fuel drip or an active fuel spray will occur.
All it takes is for that fuel source to come into contact with an ignition source – we already have oxygen in the area – and we have an environment which can create an active fire.
The ignition source to complete the formula for fire could come from a spark plug wire or an ignition coil that has deteriorated with age and is sparking, or it could be from fuel dripping on the exhaust manifold where temperatures are extreme.
Remember that not all leaks can be seen right away, some leaks also drip a bit and stop. And unlike with oil leaks, leaking fuel dissipates quickly and leaves very little residue. So, a fuel leak can easily be missed because either no residue from the leak is detected or because the leak is an intermittent leak.
2. Vehicle Fires due to Electrical Causes
Electric fires in cars are usually due to human error. Examples include:
- Batteries installed incorrectly
- Starters installed incorrectly – e.g. missing heat shields or loose wiring
- Stereos and off-road lighting on trucks not installed correctly
- High voltage connections left loose
One instance I personally saw (when the vehicle was brought in for repairs after the fire) a customer’s car caught fire when he had to change a tire on the side of the road.
He was in a hurry and tossed the car jack into the back of the trunk when he was done changing the tire – instead of putting the jack back into its holder. The jack eventually slipped into a wheel-well and, unknown to the guy, worked its way onto the main wire harness. Over time the jack, which was rocking back and forth from the car’s motion, wore through the protective wire jacket and shorted out the wire. Which eventually caused an electrical fire under his dash while he was driving down the road.
At our shop, we’ve seen stereo and off-road light installs go horribly bad, more so today because the electrical amperage requirement to run these accessories are much greater than in the old days. Many trucks even have two batteries to run all of these cool gadgets – so when an electrical short occurs a huge amount of voltage is unleashed very quickly and bad things can happen in a flash.
3. Car Fires Related to the Exhaust System
Exhaust fires, in terms of auto fires, are quite common. The exhaust system encompasses pretty much the length of the vehicle, creating lots of hot spots.
The exhaust system starts at the vehicle’s engine and runs underneath the body and out the back. The engine’s internal combustion temperatures run around 2200 degrees F, and after detonation the hot exhaust travels out the exhaust manifold where internal temperatures can reach 1300 degrees.
And if we could look into the exhaust manifold’s thick metal pipe while the engine is running, we’d see a fire inside when each cylinder of the engine detonates.
On the outside of the pipe temperatures can vary, but average anywhere from 900 degrees F and up. Most vehicles have a heat shield of some sort, but many are still wide open to help with dissipating the excessive heat. Not many people realize that under hood temperatures average around 300 to 400 degrees F, and that constant temperature when added to our dry desert climate with 8 months of hot arid days and nights really adds to the wear and tear on engine components – especially O-Rings.
As we follow the exhaust pipe further under the vehicle we come to the Catalytic Converter (some vehicles have 2 or 4 these days) that produces a significant amount of heat and more. With age, the Catalytic Converter becomes plugged and it can become even hotter. In areas where dry brush is along the roadside it’s a common occurrence to start a brush fire when a vehicle pulls off a roadway on top of low lying grasses and heat from the converter ignites dry tinder. (Many wild fires in California are started this way).
Fires can also start when heat shields are not replaced properly after repairs to the exhaust systems.
4. Car Fires Caused by Petroleum Based Fluids
Petroleum based fluids (Oil) can be found in our Engine, Transmission, Power Steering and Rear–end Differentials. Fires of this nature are usually caused by a build up that has been happening over a long period of time. But once an oil fire starts it’s hard to put out.
Ever wonder why the roads are so slippery around traffic intersections during the first rain of the rainy season? That slipperiness is oil build-up from our cars. As the years tick past in our dry climate our car oil seals dry up, not unlike our skin – which often leads to small and slow but steady oil leaks.
Leaky components make a mess of our driveways and roadways. These leaks over time accumulate and coagulate on and around the engine and chassis, left unattended they can cause damage by prematurely rotting other engine and body components, and oil is an excellent source of fuel for fire. Just think oil rig fires, they take a while to put out.
How to Prevent Car Fires
Most all of the vehicles fires could be avoidable if we just perform proper maintenance. But time and money are not always on our side, and we often skip services intending to have them performed as soon as we can – but days turn into months and then it is easy to forget vehicle maintenance altogether…until something happens.
To minimize risks for vehicle fires, have your car checked out at every oil service. Every vehicle has a maintenance service interval schedule that is recommended service by the vehicle manufacturer – and sticking to the recommendations can help to lower risks for vehicle fires in addition to a whole lot of other vehicle problems.
Keep in mind though, that a lot of fuel components are impossible to see without removing items or shields to gain access to them. For a few of these parts, in some vehicle models, it can even take more than an hour of labor to get to the point where the parts are accessed. That is why if you ever have any needed repairs around these areas, it is a good idea to have them checked while the mechanic has accessed that area of your car.
Also, fuel O-rings are not maintenance items, and in many cases fuel injectors are not either. But professionals know that they only last so long and become safety concerns after a certain point. O-rings usually start to show their age at around 60,000 miles – and age fast in the dry hot Las Vegas climate.
(Our shop performs a bumper to bumper inspection with every oil change, and we key in on all accessible safety areas. If we see parts that need to be replaced, or will need to be replaced soon, during an oil change, we’ll let you know).
And one last thing, if your car starts to overheat, don’t push it – especially in the summer. A car engine is already at an extremely high temperature, add high outdoor temperatures plus overheating and things can happen real fast. The best thing you can do is to pull over quickly – to the nearest area you can safety pull over – and turn the car off. Then get it to a repair shop.
What to Do if Your Car is On Fire
So, there’s a car on fire – what to do? Don’t be a hero.
Turn off the car and get out.
Remember, vehicle fires erupt fast, and include a myriad of toxic fumes that can overcome you in as little as two breaths.
Just get out of the car, and don’t go back in. Your purse, cell phone, wallet etc. just aren’t worth your life.
What about using a fire extinguisher? Even though everyone should have a first alert auto fire extinguisher in their car, the chances of you being able to get to it in time are small and, again, not worth it.
If you do not have experience fighting car fires, then don’t attempt it. Leave it to the professionals.
And, if the fire is near the front of the car, or under the hood, lifting the hood is the absolute worst thing you can do because you are introducing more oxygen to the fire and you are potentially exposing yourself to extremely toxic fumes and sparks.
So please, if your car ever catches on fire – just get out. Someone nearby will be able to call emergency responders.
Be safe out there!
Thanks to all of our customers for your support and trust in serving your vehicle’s needs.
Till next time, Terry and the Crew wishing you all the best!