CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Spontaneous car explosion

I keep trying to phone in but I can never get through. But I seriously want to know if someone can an answer my question. a few weeks ago i was at home in my apartment in Baltimore, when i heard a huge BOOM. the windows shook, my cat freaked out. I was laying in bed at the time, and I saw a flicker of light and I drew open my blinds to see a car completely engulfed in flames that reached as high as the second story town home that the car was parked in front of. I know from having driven by previously, that the car was just there parked when the explosion occurred. No one was in it thankfully, and no one was around before people started peeking out of their houses. I watched the fire dept arrive and quickly put it out. So here’s my question: I live in an area of Baltimore that has heavy gang issues, and i have heard of people bombing cars. But when I mentioned that to someone, they said that there are a number of reasons why a car can spontaneously explode. Is this true? can a car just blow up while sitting in park? and if so, what are the chances?

Part of the problem is that you did not witness what preceded the explosion.
More than likely, a fire preceded the explosion.
As to what sparked the fire, that could have been due to a defective ignition switch or other electrical fault, or it could have been the result of vandalism.

So–no–a car will not spontaneously explode, but it can spontaneously catch on fire, thereby causing an explosion when fumes from the gas tank are ignited. Or, someone could have vandalized the car with a firebomb of some sort, and this led to the explosion of gasoline vapors.

Explosion is one of those relative terms. I hear of candy that explodes with flavor. But it seems that spontaneous combustion of automobiles is very rare. And gasoline will burn rapidly but it is unlikely that it would explode like a bomb. I have seen 2 tanker trucks loaded with gasoline burn and neither exploded. I think the chances of the car “just blowing up” are slim to none.

@ VDCdriver- i had literally driven by moments before, and the street was quiet and dark. I had only just gotten into bed. it was about 11:40pm and the car was parked there - thus my conclusion that it was vandalized. To your point, that there may have to be fire involved by a defective ignition switch or electrical default, then my next question is, what is the probability that this could be the reason for the explosion vs a vandalism? Does this occur often? Could it happen to my car?

@Rod Knox - wasn’t a candy explosion :stuck_out_tongue: and the boom was bomb-like in its force. I live on the 3rd floor of an apartment building and the walls and windows of the building shook. the car was on a side street next to the apartment building about half a city block away.

I know this to be an area where drugs are sold and gang activity happens. So that was my conclusion. But when my friend said a car could blow up, I became concerned about the likelihood of that happening to anyone. thoughts?

In order for gasoline to explode it has to be in vapor form. Liquid gas won’t go “boom”.
According to a Coast Guard safety course I took 35 years ago one cup of vaporized gasoline can explode with the force of 15 sticks of dynamite.

So the only way I imagine this car exploding without “help” is a puddle of gas leaking out of the tank, forming a rather big zone of fumes, then a spark setting it off.
Modern cars do things after being shut off like testing the EVAP system or running the cooling fan that could conceivably generate an electrical spark.

What are the chances? Interesting question.

While it is possible for a car to explode of its own accord, I’d bet it’s very, very, very rare. Far more rare in a gang-infested area than a car exploding as a result of gang activity.

For the magnitude of explosion you describe to occur spontaneously, conditions would have to be exactly right. The tank would have to have only an inch or two of gas (be full of vapors), have a place where vapors were escaping, and an ignition source would have to come in contact with those escaping vapors. Cars today are so well designed to prevent escaping vapors (that’s what evaporative emissions systems do) that it would truely be an anomolie for all the aforementioned elements to come together.

Re: the frequency of this happenong, perhaps an insurance institute website or police statistics could provide that answer.

Thanks to all those who gave great info!! @ the same mountainbike - appreciate the answer was exactly what i was looking for. I definitely will use this forum for any other car questions I may have in the future. Again, thanks!!

Even a tank full of vapors is unlikely to explode because there’s generally not enough oxygen in there.
Needs to be 1.3 to 6.0% vapor to air.

One possibility is that there was a gas leak in the tank or fuel delivery system and someone flicked a cigarette under the car. If the gas vapor concentration was at the right level to burn, then the explosion could occur. The police may find an answer after a forensic evaluation.

1 Like

I’ve never seen a car spontaneously explode. Sounds like vandalism to me. I feel sorry for the owner of that car. I’m sure he had a fun time explaining that situation to his insurance company.

When things “really explode” it’s usually because somebody WANTED it to explode…It takes careful rigging to get a high-order explosion followed by a big fire that engulfs the entire car. The people in Hollywood are MASTERS at it…

Yeah I think you nailed it first-you live in a bad area in Baltimore. I’ve seen millions of cars over the past 60 years but never seen one spontaneously explode. Catch fire first and then explode, but not just out of the clear blue.

My mom mentioned the other day that when she lived in Washington D.C. for a year, they had a bunch of cars catch on Fire and it wasn’t vandalism. What happened was during the fall, as we all know, leaves fall on the ground from the trees and in the D.C. area where you have lot’s of trees all the leaves were piling up on the streets, driveways, and sidewalks and people would park their cars over the dry leaves which can cause fires. Now most owner’s manuals for cars will advise people NOT to park over dry leaves or any other debris that can combust so its obvious people either didn’t remember the information in the owner’s manual or they didn’t read it. In Nevada, where I live we get a lot of tumbleweeds on the road and if you run over those things, they have a nasty ability to get stuck under your car and sometimes you don’t notice until you start smelling something burning. Years ago, I once got a tumbleweed stuck on my muffler.

The good news is that it’s becoming safer. When cat converters first came out, fires were common. A match flame is generally 600-800F, and a cat converter doesn’t even begin functioning until the catalyst is brough up over 400F. The catalyst often reached temperatures well in excess of 1000F, up to about 1600F or higher. Surface temperatures of cat converters are often 800F and more.

Park an 800F tin canister, hotter than a match, on a pile of leaves or brush, and a fire is a definite danger.

Cars are becoming safer in that regard because manufacturers now are starting to put the primary cat converter in the exhaust manifold, right on the engine. They’re doing this primarily for emissions reasons, to get the catalyst hotter faster, but it has the added advantage of being up out of the way of dry brush and grass.

Explosion is a different issue. It requires the fuel to be vaporized in an enclosed container. It’s the sudden rapid expansion of the hot burning gases that causes the container to explode. If you were to light a filled gas tank, it would just blow fire, but not explode ----PLEASE DO NOT TEST THIS…argue with me if you like, but there are way too many variables and it’s way too dangerous to be testing in an uncontrolled environment.

I was a fireman for 10 years and have never seen a car actually explode.

When the car is already burning there are lots of pieces of the car that will pop and some of them are quite loud.

Tires will blow, the hydraulic bumper shocks on older cars will blow the bumpers off, those nifty gas-charged lift supports holding your hood/hatch up will also blow, etc.

I’m not saying it can’t happen, but I’ve never seen it.

Houses being blown off foundations, now that’s another story.

Bisbonian - I think you got it - I bet a tire burst on the already-burning (for whatever reason) car.

“i heard a huge BOOM. the windows shook, my cat freaked out. I was laying in bed at the time, and I saw a flicker of light and I drew open my blinds to see a car completely engulfed in flames that reached as high as the second story town home that the car was parked in front of.”

Um…a tire? Really? My money is on the gangs.

What’s really irritating is that no one reported on it in the least bit. I looked online, checked newspapers, did searches on news websites - nothing. not a mention of it. I live in the art district aka the “hood” and its not uncommon for gang activity to go unreported unless there is a death. But can I tell you, this rocked my little world for a few days. Ive never experienced anything like it.
@texases And by the way, Ive been in a convertible with the top down driving right next to a semi on the highway as the tire blew out next to my head. (and no it wasn’t a retread) My ears rang for a bit, but it was certainly not the same.
@Bisbonian - yeah there were all kinds of little pops and small explosions as it burned too. at one point, something popped and flew across the road and almost hit someone looking on.
@Katidid79 - LOL trees? whats that! haha - nope no trees on the streets in this area. Interesting fact tho :slight_smile:

You don’t have to go far off the intersection of North Ave and Charles St. to be in a seriously bad neighborhood. Have you considered moving? What about Highlandtown?

@ jtsanders - I absolutely love where I live tho. I’ve been in this apartment for nearly a year and a half. Honestly, most of the stuff that happens around here is either gang related or domestic. And this area is being slowly renovated. Lots of studios and apartments being built up and the arts district is growing. I’d like to see some of the condemned buildings get fixed up and used. As it is, they’re like missing teeth in baltimores smile. I love my city :slight_smile: