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Heater coil

heater coil I bypass it. because it will take a lot time to get it out. are the heater that you plug in 12 volt outlet any good. just need for frost on windshield. and were do they sell them.

A butane-operated heat shrink gun might do the trick. They cost about 25USD and are sold everywhere.

With respect to mechaniker, I would recommend avoiding anything that burns hydrocarbons, like a butane operated heat shrink gun, as a defroster. It’ll put out carbon monoxide.

what city? driving in cold climates with no heater circuit will freeze your butt off. no plug in 12v heater is going to have any impact on a car with no heat. any auto store, like orielys, or autozone sells 12v heaters but they are basically toys. you need about 100 amps to actually get heat you can feel. if you hardwire a heavy gauge wire directly into battery harness you could make it work. get a 1000w inverter and than use a standard 120v household space heater. lots of work vs fixing heater core

Yes it will take along time.
Time you must invest.
Time to fix it right…whatever ‘IT’ is that needs a heater…CORE .

Heat from the cooling system of the engine is free where you use more energy to run an electric defroster. I tried one as a rear window defroster and it didn’t work very well. You might as well bite the bullet and install a new heater core.
As for butane heaters, Consumer Reports tested a battery operated CitiCar back in the early 1970s. The tested car had the optional propane heater and CR reported that it really fogged up the windows. The byproduct of combustion is CO2 and H20 (water).

If you try to improvise a “defrost” sol’n, be careful you don’t accidentally crack the windshield. To avoid cracking the glass, the windshield needs to heat up evenly and slowly. Avoid devices that produce locally concentrated high temperatures.


Please tell us the make, model and year of your car

Butane (C4H10) does not produce any carbon monoxide (CO) when combusted.
The chemical reaction is 2C4H10 + 13O2 -> 8CO2 + 10H2O

The butane gun is applied to the outside of the windshield, not to the inside.
A cheap butane gun can produce temperatures of 800-1400ºF which could cause stress fractures in the glass if used inside the car to melt ice on the outside of the windshield. (I did not think that needed saying.) Once the ice is melted, the anti-freeze in the windshield washer solution should prevent further ice build-up, provided the temperature is not too cold.

Having a garage replaces a heater core is expensive.

The OP is, I believe, referring to a replacement for the inside windshield defroster. For outside frost and ice, there’s a device called an ice scraper.

For inside duty, the OP is probably going to have to bite the bullet and get the core replaced.

With respect, mechaniker, butane is subject to the production of CO just as any other hydrocarbon fuel is. As with gasoline, complete combustion produces CO2, any incomplete combustion results in CO

2) Incomplete combustion of butane
If there is not enough dioxygen to burn all the butane then combustion is incomplete:
In addition to other products it appears a black solid compound ( carbon ) and a gaseous compound colorless, odorless and very toxic ( carbon monoxide )

Chemical reaction is then :
Butane + dioxygen → carbon dioxide + water + carbon + carbon monoxide


Drrocket, my understanding of the OP’s question was the same as yours. I understood that he was looking for a quick & dirty temporary replacement to be used inside the passenger cabin.


You shouldn’t assume that OP knew you meant to use the butane torch outside the vehicle

assumptions make an ass out of u and me

pardon my “french”

The OP could try a few spoonfuls of black pepper or mustard seed in the radiator if the leak is not too bad. If one is at the point of no heater at all with winter coming on it’s always worth a shot.

Might not be a bad idea to check the hose connections also. Sometimes those tiny leaks at the hose fittings can ooze into the passenger compartment and cause one to believe the core itself is leaking.

“Any auto store, like O’Reillys, or Autozone sells 12v heaters but they are basically toys.”

I agree with @Cavell here because I bought one of those “toys” years ago from JC Whitney and it almost burned up my car. I had a VW bug and in the winter I discovered that it had a non-heater. I ordered a 12V one from a catalogue and plugged it into my newly installed cigarette lighter. I let it run to heat up the bug as I was waiting to pick up my date on her front porch. I looked down at the bug and saw a glow from inside and I thought all was well. Not! The heater burned out my new cigarette lighter plug and about a foot of the electric cable. My date’s dad drove us to the movie theater in town because he did not trust my mode of transportation. Besides…it smelled like burnt popcorn inside the little bug and I got rid of it before the smell went away. Fix your heater core and be warm the right way.

Butane is completely oxidized when burned in air composed of 21% oxygen.

A little math:
Butane is usually sold in 8oz cans which lasts about 4 hours in a heat shrink gun.
Thus a gun used for 15 minutes consumes about 0.5 oz of butane.
The stoichiometric A/F ratio of butane is 15.5.
Therefore a stoichiometric 15-minute burn of butane requires 7.75 oz of air.
Air density at 15ºC is 1.225 kg/m^3 or 1.22 oz/ft^3.
Hence the volume of air required for a 15-min stoichiometric burn of butane is 6.3 ft^3 — not zero, but not very significant.

Excess input air to the flame above that computed above would further decrease the likelihood of CO formation. The excess air would be returned to the car cabin in the burn exhaust.

When any hydrocarbon is burned at below a stoichiometric A/F ratio, the hydrogen atoms alway capture the oxygen atoms first before the carbon atoms do. Some carbon atoms capture two oxygen atoms, some only one, and some carbon atoms capture none. These oxygen-less carbon atoms glow yellow in the flame and emerge as black soot particles. If the flame is not yellow and soot is absent, then no CO is being produced.

This is my last response on this topic (or any other) for a while. I think I’ve beaten this horse to death.


As I remember, school buses have auxiliary heaters under some of the seats. If you don’t mind how things look, you might find a junked school bus and obtain one of these heaters. I believe they have a fan in them. You could mount the unit on the transmission hump or console and run heater hoses to it, and connect the fan through a switch to the fuse panel. Also, mount a fan on the steering column and direct its flow to the windshield. That is essentially the heating and defrosting system many cars used in the 1930s and 1940s. It’s crude, but it would work better than an electric heater that plugs into the cigarette lighter.

I like @Triedaq 's idea of just installing a heater core under the seat. Seems like a good temporary fix. As long as a method to route the two firewall hoses could be found, a person could probably purchase a used heater core and temp control at a junkyard out of most any small-ish vehicle and have a nice toasty car for the winter, then fix it the right way come summer.

I still maintain that burning a butane heater, or any other hydrocarbon fuel, in a passenger cabin is a bad idea. A really bad idea. Conditions for full combustion are rarely perfect, and the risk is too great. If all the conditions meet your math model, nothing happens. If not someone might die. You may feel free to burn a butane heater in your car if you like. I still recommend against it.

Math models are invaluable. But they’re not perfect. The variables are… variable. When the risk is as great as CO poisoning, it ain’t worth it in my opinion. Sorry, but I stand by my recommendation.

The idea of motoring around with a fuel based heater would not be my cup of tea. Other than a potential CO issue there’s also the issue of what could happen during a collision.

Some may remember not many months ago the story on the news of the young lady somewhere in the Mid-Atlantic region who was taking a nap in her car and died due to gasoline fumes from a spare jug of gas in the car.

There’s a lot of ways something like this could go wrong…