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Water pouring out of tailpipe

My m-i-l just called and posed this question. What could caause water to pour out of the tailpipe of her '99 Camry? They had started the car and a neighbor came over and told her there was water coming out of the tailpipe. She looked, and it was still “pouring” out. I asked her if was green liquid (coolant) and she didn’t know, it was getting dark. I told her not to drive the car. If we get nothing by Monday, she will call the dealer, but any help in the meanwhile would be appreciated.

Most likely water in the gas and nothing to worry about if all your fluid levels especially antifreeze remain stable.

“Water in the gas”? How would that work? Rocketman

Seriously . . . water . . . from whatever source, normally doesn’t “pour” out of the tailpipe. Water droplets . . . the result of some emission control systems (the bad exhaust being partially converted to water vapor) can happen, it looks like steam. But water pouring out is a tough one. If it were my car, like waterboy I’d look at the fluid levels . . . coolant . . . oil . . and pay attention to the condition of either, to see if your fluids are contaminated . . . oil in the coolant or vice-versa, which is a bad thing, suggesting a gasket leaking somewhere. Rocketman

Using gasoline makes water and CO2. Use a gallon of gas, make about a gallon of water. Warm weather it’s vapor, cold weather it’s liquid until the exhaust system heats up. That’s the ‘water in the gas’, I’m guessing.

It is most probably condensation in the muffler and the pipe. See it all the time and there is nothing wrong with gas or the car itself.

If it were H2O in the gas, describing the amount, the engine will probably would not even start.

With all do respect to the expertise on this site and those answering this post I must ask…How can ANY coolant or oil drip out of the tail pipe of an engine that is running??? the only explanation is condensate as mentioned!

I have respected your answers as you are extremely knowledgeable and provide really great answers to so many people. Condensation is 1 way for water to appear in gas and I have heard they measure oil shipments by shooting a water plug into the oil line to measure transmission and loss. I have seen water dripping out of my own tailpipe and attributed it to a non essential concern. Please correct me if I have given bad info!

Checked with my f-i-l, there was more than a pint running out when he saw it over 4,5 minutes, that;s not condensation.

Sorry, father-in law,
I trust his observation that more than a pint of water in 4 minutes is not condensation.

A pint of water running out of the tailpipe in 4-5 minutes is not water vapor or condensation. Something is wrong. Wait for tomorrows daylight and check the fluid levels, paying close attention to the contamination I mentioned earlier. I wouldn’t run the engine until your mechanic looks at it . . . a few minutes of an engine running with coolant in the motor oil could become very expensive, very fast. What are the particulars on this Camry? Year? Engine? Mileage? Good maintenance? Overheating ever or recently? Rocketman

I Have Seen Water From Condensation Literally “Run” Out Of A Tailpipe …

… more than just a steady drip.

Sometimes it collects in the exhaust pipe, resonator, muffler, and tailpipe, especially when the car is first run and the exhaust system is not sufficiently hot to vaporize the water and dry things out.

It “pools” in low places of the exhaust system, possibly just dripping from the tailpipe and sometimes tiny drain holes. When one accelerates the car from a stop, goes slighty uphill such as a driveway, or even bounces the car a little while driver and passengers are entering or exiting, the water flows out. It either comes out because the car is acclerating away from it or gravity is pulling it to the lowest point.

Once the exhaust system really heats up after driving, the water is just vaporized and one sees the exhaust as steam and often just a few drips.

Temperature and humidity can exacerbate the situation. Making one or several short trips and then parking the can help create water in the system that is just waiting for an opportunity to run out.

Check the fluids. I’ll bet there’s nothing wrong.

Watch other cars pull away from traffic lights. Pay particular attention to tailpipes of cars with really steamy exhaust (the car is probably not warmed up, yet) when they accelerate after waiting at a light on a cold day.

Here’s another one that has had me alarmed. Only once in a rare while, driving in heavy snowfall, I have stopped the car only to find steam rushing from my grill. I become immediately concerned that the car is overheating. It turns out that with just the right temperature, humidity and snowfall, the steam is just from snow being melted and vaporized after collecting on the outside of the radiator. It gets me going every time.

Just have him put a bowl under the exhaust, collect some, see what it is, check the coolant level. I bet it’s condensation. For a cold engine the water can collect in the low point until the exhaust forces it out.

Thanks all, I’ll go check it out tomorrow.

Until the exhaust pipe gets hot you will have some water. A pint doesn’t sound like too much. I have seen more than that in a situation like yours and there was nothing wrong with the car. If the coolant reservoir is at the right level, it’s OK.

Wouldnt it be steam not solid water

If your catalytic converter is doing its job, it will convert some of the exhaust gasses into water vapor, especially when the car is first started and is running a little rich. If you only drive the car on mainly short trips, this water vapor can collect in the exhaust system rather than evaporating from the heat generated from longer trips.

The next time you pull up to a stop light near your house, where the cars are not warmed up yet, take a look at the tailpipes and you will see water coming out, especially if it is a truck with a large diameter exhaust pipe.

This is nothing to worry about.

This is right so let’s echo it. A catalytic converter converts unburned fuel into CO2, Nitrogen, and Water. It’s easier to notice when the tailpipe is cold and when the mixture is rich.

If your M-I-L is calling check for trouble codes.

In cold climates water can drip out of a tailpipe in significant amounts. It’s source is combustion, it’s stream is from condensation.

Gasoline is a hydrocarbon, hydrogen bonded to carbon. Air is nitrogen, oxygen, and argon (with some misc of about 1%). When the hydrocarbon atoms split, the carbon bonds to the oxygen (forming carbon, dioxide and carbon monoxide) and the hydrogen binds to the oxygen forming H20 (water vapor). In a cold exhaust, the water vapor condenses on the insides of the exhaust system and drips out, sometimes prolifically.

Nitrogen also bonds to oxygen forming oxides of nitrogen (NOx) and some unburned hydrocarbons also come out, but they’re irrelevent to the question so I’ll sjip them.

Bottom line:
inputs to the combustion chamber are
HC, Ox, N, and Ar

Outputs are
O (especially after the cat converter splits up the Nitrogen and Oxygen atoms)
and H2O…water