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-   -   Why does a car catch fire? (https://www.team-bhp.com/forum/technical-stuff/71367-why-does-car-catch-fire.html)

Team, any valid reason why do cars catch fire either during drive or when parked idle. Heard lot of such incidents and as a precautionary measure would like to hear from BHPians.

Electrical short circuit and sparking near the fuel lines or other combustible material is the most common cause of automotive fires worldwide. This is followed by other causes like overheating of certain components of the automobile leading to other parts catching fire, abrasion of components resulting in sparks and heat and subsequently fire.

The best way to avoid this is to make it a habit to check fuel lines for leakage/worn out joints and their proximity to electrical wiring and of course keeping a portable working:D fire extinguisher in the car.:thumbs up

Recently i did a nonstop 5 hr drive without any single break and later was worried if some components would get over heated due to continuous driving .

Is it safe to do continuous driving for say 5-6 hours? ( i was driving in the night with family, so didnt want to stop in a deserted place).

Are there any components in the car that will cause firing due to continuous driving?

Suggestion needed.

Battery/Electrical short circuits, due to faulty OEM installation or after market ones.
Faulty LPG installations or error in operation.
Old cracked fuel pipes in the engine bay. (Our 800 caught fire this way but Thank God nothing more happened).
Vandalism/riots stupid:
No Bio or fuel breaks ? What speed were u in and what is ur tank capacity ? 5- 6 hours w/o the above breaks is quite an achievement.
IMHO depends on ur car. If it is serviced properly and it is good running condition then its ok.
If I have a 10 year old abused car then probably its not a good idea.I usually take breaks after around 2 - 2.5 hours of continous driving.

As said by others, short circuit/sparking with presence of inflammable objects leads to fire not just in cars but for most common fires at home/factories etc.

If the car is generally well maintained, and esp. if the cooling system is working optimally and there is no sign of overheating, it should be perfectly fine. I have myself been in cars and know other people who have driven non-stop for hours, even in daytime (hotter). No issues!

One of the reasons for electrical short circuit in automobiles is the improper clearances between the wiring harness and the moving parts. I remember the experience of one of our test mules catching fire due to the wiring harness shorting with the body, this happened as the harness was hanging loosely and started fouling with the I shaft of the steering mechanism. Incidentally, this wire happened to be the supply wire which connects to the starter motor of the vehicle, this is capable of carrying currents up to 65 Amperes. The vehicle after this short circuit was in a ball of wire, definitely a great learning experience for me.

Running the car for 5 or 6 hours without stop by itself does not lead to any fires.

The biggest cause of vehicles catching fires (except when they are set to fire) is electrical short circuit. And the biggest reason for the short circuiting is faulty wiring, faulty after-market fitment of electrical parts, CNG/LPG kits etc.

Regarding parts getting hot, the exhaust system of the car will surely be very very hot after about an hour of driving. Parking it over dry grass or any similar inflammable article will be dangerous.

I have driven both my cars all through the night & covered around 600-700 kms so travelling 5-6 hours is not at all an issue till you keep an eye on coolant, engine oil etc. Also while driving when you like you check fuel & speed you should also keep a track of temperature because this is the first thing which indicates overheating.

Yes it is absolutely safe to drive more than 5-6 hours, Even driving continuously for days wont cause a Fire.

The most common cause of fire in automobiles is triggered either faulty/Tampered electrical system, improper modification to alternate fuel like LPG/CNG or leaking fuel.

1) Electrical systems :
People do mods just for the sake of style. They end up overloading systems in the first place ( also the reason why many face drained battery issues ).
But here, comes another part, installation of the mods. Most of the people are just not aware of what they are messing up with and whom they are allowing to work on cars. The so called " mods " shop have menpower that do not know anything. They are just show off guys and do the job roughly, quickly without fit and finish. Even dressing of cables is not done.

This is main reason.

Next, servicing. Not all independent garage owners are good. Agreed that there are some who are really good and know their job, others are just not enough to handle anything more than an oil change at the most.
Many car owners go to these garages. Chances are that the staff at these garages may not be trained and again its as good as mod job. Chances of fire are high again.

CNG/LPG improper installation have just raised the no. of cars catching fire.

In short, the main reasons are :

1) Modifications done in improper manner, specially electrical.
2) Cabling not checked, improperly dressed in case of modded car.
3) Fuel lines. Rats are notorious here.
4) Improper maintenance. After lets say 1 lakh kms, its good to have the cables checked and if required changed irrespective of the car. Operating condition plays a major role.
5) Adding LPG and CNG from incompetent places.

That said, we have M800 with CNG kit that has run 45K kms on CNG. This was done from an independent garage in my city. No issue from leakage POV till now.

CNG is safer than LPG, so CNG is preferred over LPG IMHO.

Here, I would like to add that Indian manufacturers provide very poor headlights ( which is a good thing if we consider that most Indian dont know how to drive in disciplined manner ). Very small amount of people are there who modify headlights for better night driving, but they end up going to incompetent garages and eventually pay the high price.

In this Aspect ,Are Diesel Cars comparatively safer?

In which respect? Catching fire? I guess they are equally susceptible to the danger.

I have driven my car Swift for like 5 hrs nonstop, Astra for about 10 hrs nonstop (driver change ofcourse).

Cars don't catch fire driving non-stop.

Main reason for fire is short-circuit, modifications to a car and poorly maintained car.

Pshaw... 5 hours is nothing, ask any highway driver here. As long as the temp gauge stays where it should be, you can keep driving until you're out of fuel :D.

@prince_pervez, 6 hours could indicate a distance travelled around 400 to 500 kms on average. Shouldn't be a starin on the capacity of even a small hatchback.