Can a car engine run on water?

How an engine cooling system works

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A car engine produces a lot of heat when it is running, and must be cooled continuously to avoid engine damage.

Generally this is done by circulating coolant liquid usually water mixed with an antifreeze solution through special cooling passages. Some engines are cooled by air flowing over finned cylinder casings.

A water-cooled cooling system

A water-cooled engine block and cylinder head have interconnected coolant channels running through them. At the top of the cylinder head all the channels converge to a single outlet.

A pump , driven by a pulley and belt from the crankshaft , drives hot coolant out of the engine to the radiator , which is a form of heat exchanger .

Unwanted heat is passed from the radiator into the air stream, and the cooled liquid then returns to an inlet at the bottom of the block and flows back into the channels again.

Usually the pump sends coolant up through the engine and down through the radiator, taking advantage of the fact that hot water expands, becomes lighter and rises above cool water when heated. Its natural tendency is to flow upwards, and the pump assists circulation.

The radiator is linked to the engine by rubber hoses , and has a top and bottom tank connected by a core a bank of many fine tubes.

The tubes pass through holes in a stack of thin sheet-metal fins, so that the core has a very large surface area and can lose heat rapidly to the cooler air passing through it.

On older cars the tubes run vertically, but modern, low-fronted cars have crossflow radiators with tubes that run from side to side.

In an engine at its ordinary working temperature, the coolant is only just below normal boiling point.

The risk of boiling is avoided by increasing the pressure in the system, which raises the boiling point.

The extra pressure is limited by the radiator cap, which has a pressure valve in it. Excessive pressure opens the valve, and coolant flows out through an overflow pipe.

In a cooling system of this type there is a continual slight loss of coolant if the engine runs very hot. The system needs topping up from time to time.

Later cars have a sealed system in which any overflow goes into an expansion tank , from which it is sucked back into the engine when the remaining liquid cools.

How the fan helps

The radiator needs a constant flow of air through its core to cool it adequately. When the car is moving, this happens anyway; but when it is stationary a fan is used to help the airflow.

The fan may be driven by the engine, but unless the engine is working hard, it is not always needed while the car is moving, so the energy used in driving it wastes fuel .

To overcome this, some cars have a viscous coupling a fluid clutch worked by a temperature sensitive valve that uncouples the fan until the coolant temperature reaches a set point.

Other cars have an electric fan, also switched on and off by a temperature sensor .

To let the engine warm up quickly, the radiator is closed off by a thermostat , usually sited above the pump. The thermostat has a valve worked by a chamber filled with wax.

When the engine warms up, the wax melts, expands and pushes the valve open, allowing coolant to flow through the radiator.

When the engine stops and cools, the valve closes again.

Water expands when it freezes, and if the water in an engine freezes it can burst the block or radiator. So antifreeze usually ethylene glycol is added to the water to lower its freezing point to a safe level.

Antifreeze should not be drained each summer; it can normally be left in for two or three years.

Air-cooled engine cooling systems

In an air-cooled engine, the block and cylinder head are made with deep fins on the outside.

Air-cooling through fins

Frequently a duct runs all around the fins, and an engine-driven fan blows air through the duct to take heat away from the fins.

A temperature-sensitive valve controls the amount of air being pushed around by the fan, and keeps the temperature constant even on cold days.

‘They killed the last guy that did that’: Man claims his car runs on water instead of gas, resurfacing vintage conspiracy theories

Some conspiracy theories just refuse to die, and right now a viral TikTok is reviving a true classic: The idea of a secret invention that allows cars to run on water instead of gasoline.

Viewed an astonishing 8.8 million times in the past two weeks, the original TikTok shows TikToker @bilongaz pouring bottled water into a device full of liquid in the trunk of a car. The caption reads, “Everyone complaining about gas prices and mine runs on water.”

As many commenters pointed out, this liquid-filled device is almost certainly just the car’s cooling system. There’s no such thing as a water-powered car, and to be honest, this TikTok seems like it was intended as a casual joke by someone with a car-themed account.

However, many commenters drew connections between this video and long-running conspiracy theories about water-fueled engines. In particular, some joked about the unfounded rumor that the Pentagon assassinated amateur inventor Stanley Meyer for creating a water-powered car. This story is so popular that it was even a punchline on That ’70s Show, based around the idea of gas companies controlling society. (There’s also a long history of people claiming to invent water-based fuel cells as scams or hoaxes.)

One of the TikTok’s most viral responses was a duet posted by @indubwetrust, viewed more than 3.8 million times. “I don’t know if you know this but they killed the last guy that did that,” he says. “They didn’t even try to cover it up; they just killed him.”

The comments sections for both TikToks are full of conspiracy theory references—mostly facetious, but some more serious. “My teachers best friend did this but it was bigger and I don’t know if this the real thing but a few days later he had a black tinted car follow him,” one of the more conspiratorial responses reads.

Meanwhile @bilongaz’s other TikToks are being flooded with jokes about him being “disappeared” by the government. Apparently it’s an ominous sign for him to only post one other TikTok in the past two weeks. “government postin his drafts fly high,” one response reads.

Just to reiterate, there’s no such thing as a water-powered engine, and no reliable evidence of a government coverup. As Politifact and other fact-checking outlets point out, this hypothetical fuel cell (which would split water into hydrogen and oxygen) would defy the laws of physics. It’s completely unclear how it might work, drawing comparisons to other impossible inventions like a perpetual motion machine.

The Daily Dot has reached out to @bilongaz and @indubwetrust via TikTok comment.

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Can You Really Run Your Car on Water?

Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.

Updated on February 07, 2019

Since posting instructions for making biodiesel, many readers have noted that many cars (including mine) run on gas, not diesel, and asking about options for gas-powered vehicles. In particular, I’ve gotten a lot of questions about whether it is true that you can run your car on water. My answer is yes. and no.

How to Run Your Car on Water

If your car burns gasoline, it won’t burn water per se. However, water (H₂O) can be electrolyzed to form HHO or Brown’s gas. The HHO is added to the engine’s intake, where it mixes with the fuel (gas or diesel), ideally leading it to burn more efficiently, which should cause it to produce fewer emissions. Your vehicle is still using its normal fuel so you will still be buying gas or diesel. The reaction simply allows the fuel to be enriched with hydrogen. The hydrogen isn’t in a situation where it could be explosive, so safety isn’t a problem. Your engine shouldn’t be harmed by the addition of HHO, but.

It’s Not So Simple

Don’t be discouraged from trying the conversion, but take the advertising with at least a couple of grains of salt. When reading the ads for converter kits or instructions for doing the conversion yourself, there isn’t a lot of talk about the trade-offs involved in doing the conversion. How much are you going to spend making the conversion? You can make a converter for about $100 if you are mechanically inclined, or you could spend a couple thousand dollars if you purchase a converter and have it installed for you.

How much is the fuel efficiency actually increased? A lot of different numbers are tossed around; it probably depends on your specific vehicle. A gallon of gas might go further when you supplement it with Brown’s gas, but water doesn’t spontaneously split itself into its component elements. The electrolysis reaction requires energy from your car’s electrical system, so you are using the battery or making your engine work a bit harder to perform the conversion.

The hydrogen that is produced by the reaction is used to enhance your fuel efficiency, but oxygen also is produced. The oxygen sensor in a modern car could interpret the readings such that it would cause more fuel to be delivered to the fuel-air mixture, thereby decreasing efficiency and increasing emissions. While HHO can burn more cleanly than gasoline, that does not necessarily mean a car using enriched fuel would produce fewer emissions.

If the water converter is highly effective, it seems that enterprising mechanics would be offering to convert cars for people, who would be lining up to increase their fuel efficiency. That isn’t happening.

The Bottom Line

Can you make fuel from water that you can use in your car? Yes. Will the conversion increase your fuel efficiency and save you money? Maybe. If you know what you are doing, probably yes.