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Car mechanic error sets car on fire?

Hello everyone. I took my car (Toyota Corolla 2004) to a car mechanic today to get the battery changed.

Turns out, the car mechanic made in error in placing the new battery. The car actually LITERALLY lit on fire for about 30 seconds. The car mechanic then needed to use a fire extinguisher to put it out. Afterwards, I guess the car mechanic and the manager said that the battery accidentally touched something, and only the metal casing holding the battery burned. However, they told me that nothing serious was actually burned and they said that everything would be okay. They then charged me full price, and I paid it.

I then drove the car home and nothing seemed out of place and everything seemed fine. However, I am a little worried about the car and whether or not the mechanic did in fact do an honest evaluation. This is a situation I’ve never heard of before, and I would really appreciate any advice or input from you all!

A car battery has a lot of stored energy in it. Especially a new one. One way mechanics check a battery is to connect it to a special heater element for this purpose. If the battery is good, it heats up the element red hot just like one on a stove.

I expect they somehow did the same thing, only accidentally. They shorted the battery out in the process of installing it. The huge amount of current flow caused the battery to overheat and catch on fire.

They could have done other bad things. Like installing it backward. But if they did that, I expect you wouldn’t have been able to drive the car home. Suggest you inspect the battery and the wiring around the battery. If it all looks ok, cross your fingers, and hope for the best.

No harm to carry around a small fire extinguisher in case there’s something unknown yet to come.

+1 with George.
They likely attached the negative before the positive terminal and then shorted the positive terminal across it and some ground point - a boneheaded move but luckily nothing bad happened.
Since they replaced the battery they fried, you’re most likely good to go.

Perhaps look around the area of the battery to see if any paint is burned off, etc. Bare metal will rust eventually so they should do something to stop that from happening. If you don’t see anything out of the ordinary, you’re probably fine.

Thanks for the advice! I guess one thing I’m a little concerned about is that I understand that they might have shorted the battery, but literally it bursted into flames.

It’s really reassuring to hear that nothing bad likely happened, but I’ve honestly never heard this happen to anyone else before. Is fire something that happens often enough in car mechanic shops such that I really shouldn’t be worried?

There’s a lot of stored energy in a battery. If you short the terminals, you can weld with that current.
It shouldn’t happen but people do make mistakes. If you slip a wrench on a positive terminal and have it cross ground, it can get ugly.

Pop the hood and make sure you don’t see anything burned near where the battery is located. If you don’t, you’re fine.

@Remco: “Since they replaced the battery they fried, you’re most likely good to go.”

I don’t see anything suggesting they did install a different battery.

I assumed they replaced the deep fried battery because it would make sense because that’s really the only solid option – but you’re right. We could be dealing with knuckleheads so that leaves the question:

@supersmashluva: did they indeed replace that fried up battery?
IF they didn’t, they should have.


No, in fact, they did NOT replace the fried up battery. I’m not exactly sure what they did, but they did not replace the fried up battery. Eventually it was concluded that it “worked” and they had me drive off with it, and I didn’t notice anything wrong.

However, would it be my right to go into the store and ask for a new battery. One that wasn’t burned…?

When I first read your issue, I assumed it was just a slip of the wrench across a terminal or maybe the battery hold down. One would assume they did the right thing and replaced the battery they shorted. Since they didn’t, you definitely want to make sure they actually didn’t do damage to your car.
They may have fixed it enough just to get you out of their shop so they can forget about their screw up.

I don’t mean to worry you:
Everything may be okay but you do want to check under your hood.
You may not be very experienced with cars so perhaps ask someone like a family member or work mate that may know a little more about cars look under your hood and see if there’s any evidence of stuff having cooked.
Make sure that there’s no area that looks like it had paint on it that now does not. Wires should not look brittle or shriveled up. Look for evidence of them having taped stuff up with electrical tape or shrink tubing. It should all look pretty tidy.

Also, if they shorted the new battery, I’d insist on a new one. Shorting across a battery drastically shortens its life.

I understand that they might have shorted the battery, but literally it bursted into flames.

@supersmashluva: I agree with Remco, there’s no way you should have been sent away with a battery that had burned, regardless of how or why it burned, or what the perceived damage was. You may have a damaged battery, or it may be fine, but that’s going to be hard to accurately determine. But given that you paid for a brand new battery, you should not accept one which is potentially damaged.

The way this shop handled this bothers me. It seems they hoped they could persuade you to accept their mistake. I don’t think this was just a mechanic’s mistake, I think it is management’s questionable behavior. They told you everything is fine, but from the sounds of it, I wouldn’t trust them. Keep your paperwork. If you can get them to document in writing what they claim actually happened, what burned and why, etc, that would be useful. Thank them politely for that. Then find a different shop, ideally a locally owned auto electric shop, and have them make their determination if you have any cause for concern. Offer to pay that shop for their examination, and if they find a problem or have cause for concern, ask them to put that in writing so you can take it to the first shop and insist they make it right. Ideally though, you would have any repairs done by the auto electric shop, not the first place - I just don’t trust them. I’m sorry you have been treated this way. Good luck with this.

Unless you can post pictures of the area around the battery, I don’t think anyone can make a really good suggestion as to what you should do other than take your car to another, trusted independent mechanic for an evaluation. You may have to pay for this, but if the independent finds damage due to battery installation, then you should contact the first mechanic and give them first chance to mitigate the problem, that means they fix the damage and compensate you for the cost of the independent mechanics opinion.

If they do not agree to do this, then have the independent make the repairs, document everything, including before and after pictures of the damage and then present the bill to the dealer. If they don’t pay, take them to court. You must give the first mechanic first chance at fixing the problem though.

My concern here is less for the battery and more for the surrounding wiring. If flames were involved, then there is a chance of seeing melted plastic on the battery case, burned paint and melted insulation on the wiring which will lead to problems later on. Also the chemicals used in fire extinguishers is very corrosive to wiring.

Thirty seconds is an eternity with a fire and the competency and ethics of the shop could well be questionable.

It’s bad enough to make a mistake on such a simple procedure but to dismiss any potential damages and still hit you with the full bill is a bit crude. Without seeing the actual damage, my opinion would be that at a minimum they should have just eaten the cost of the battery replacement as a PR measure.

Batteries don’t burn. If a fire extenguisher was used what was burning? The battery on that car is out in the open, resting between the air filter housing and head light housing. I can’t imagine anything igniting from shorting out the battery. If shorted out, the insulation on wires and cables would melt and smolder but not actually ignite. If you post a photo of the battery possibly someone can make a SWAG as to what happened.

I presumed they put a new battery in too, to replace the burned one. It may be though that the battery condition is still ok. This can be determined by a load test. Suggest to have this done to confirm the battery is ok. It might be better to have this done by a separate shop to avoid conflict of interest. In my area Sears will do a battery load test for free. Tell them what happened, and why you are concerned.

I’m assuming there is no clearly visible damage to the battery case. No warping, etc. And it looks ok on the inside too, no warping of the plates, etc. Don’t look inside the battery yourself unless you have experience with batteries. There’s a host of safety precautions involved. Let a pro check it for you.

There’s a slight chance the load test will be ok, but the battery remains damaged internally. If so, this will reveal itself at some point in the future. At which point the battery warranty should yield you a new replacement battery.

Fires in cars are not that uncommon. Usually they don’t occur in well run shops, but there’s always a possiblity of an accident I guess.

I have a friend who had a fire in her car. It was caused by the starter motor selenoid contacts going bad, and on time when she started the car the contacts welded in the “ON” position. She parked the car in “P” after a short trip, and apparently didn’t notice the fact the starter motor was still running. She hear sirens, and looked out the window of her apartment a few minutes later to see flames coming from her car parked in the street. The result wasn’t a pretty sight.

Hello everyone. Thank you for all the help! I really appreciate the advice.


I just went to another car mechanic shop. They inspected the car, and they DID in fact find that there was significant damage. The estimate they gave was $1800 which I have absolutely no intention of paying out of my pocket.

There were some requests for pictures, I did take one, and I really appreciate any help you guys would have to offer!

Wow - I am very glad you got it checked out as that could have caused all sorts of gremlins down the road.
You may need to go over to the original shop and nicely but firmly ask them what they are going to do about it. You don’t have to point out they are incompetent and knuckleheads - that’s pretty obvious and won’t get you anywhere.
Give them a way to save face by saying something like “where people work hard, people sometimes make mistakes but I need this fixed”. No need for either party to get upset. They have insurance to cover for stuff like this. They can offer to fix it but they should have done that to begin with, hat in hand, profusely apologizing for being stupid and accepting full responsibility. It is too late for them to do that now.

In the unlikely event they end up not being responsive, you may need to go to small claims court, though.

Good luck with it.

You should hold them responsible for every dime it takes to put the car to the way it was before this incident happened.
The fact that they would hand the car back to you with damage like that is pretty low and offhand I might say that they put the battery in backwards and that’s what the apparent char mark is on top.

What will be interesting is what they have to say when told they should pony up for making it right.
They may very well claim that there’s no way there could be that much damage and that they will take care of the problem. My response would be that they mangled a battery installation so why should they be trusted to sort it all out.

I can’t believe they didn’t even clean off the fire extinguisher powder. That’s really sloppy.

...they mangled a battery installation so why should they be trusted to sort it all out.

I agree totally. I would not allow them to touch the car again. Not so much because of the mechanic’s mistake, but the action of the manager to try to assure you it was ok when it was obviously not. Charging you for that damaged battery strains believability. Just seeing the photo makes it clear that this was damage…and they charged you full price? Incredible.

Have the other shop do the repair and present the bill to the offending shop. If they balk, remind them that they attempted to deceive you, and you have more than enough reason to not trust them. Allowing the unscrupulous first shop do the repair is more risky than going to court.

Analyzing the picture you posted – With fire extinguisher residue on top of the batery (!) and even on top of the hold-down bar (!!!), I’d infer that they shorted the battery AFTER they put it in place. Maybe a wrench-to-ground when they were to tightening the pos terminal (and having neg already improperly connected). So, they clearly left in the old battery (!!!).

I can only second the other comments here about the competence and ethics of the original shop, and with the lay opinions here that they are legally responsible. I hope you can find a way to resolve this without having to pay as much for legal help as you would pay to get the car made whole.