‘Why is water coming out of my car's tailpipe?’ [Newbie Guide]

As part of driver’s education, aspiring motorists learn about the parts of a car and how these are dedicated to a specific role. The headlamps light the way ahead, the doors provide access to and from the cabin, the steering wheel allows users to turn the vehicle, and so on. 

Water instead of smoke coming from the tailpipe might confuse the new driver

As such, it comes as a surprise when certain components seem to be working in a way that seems uncharacteristic, even downright odd. Case in point: finding water coming out of the car’s tailpipe, when the vehicle was not submerged in any way. Knowing that the engine is supposed to release smoke, should you automatically assume that something is amiss? 

Not just yet. To refresh the memory of those driving lessons, the tailpipe is part of the car’s exhaust system that vents out gases from the fuel that the engine burns. The byproduct of that combustion is smoke, which is what we readily expect to see coming out of that tube from under the rear bumper especially under acceleration. And when you find water dripping from the tailpipe, there are several possible reasons for this. 

Condensation

Aside from smoke, other results of the internal combustion process are nitrogen, water vapor, and carbon dioxide. As they leave the combustion chamber, both the carbon dioxide and water vapor tend to mix. 

This leads to the formation of condensation or water while the engine cools down, and eventually the tailpipe will have a small amount of water dripping out of it. After the vehicle has warmed up, the heat will dry out the remaining water, stopping the dripping. 

Engine heat

Water vapor is also present when the car is started in a cold environment. Before the oil starts circulating to cool the engine down, the engine’s components generate heat through friction for the first two minutes after ignition. 

A hot engine operating in a cold environment can result in water droplets forming in the tailpipe

When the heat of the engine’s operation meets the surrounding cold air, this will also lead to small water droplets on the exhaust tip, accompanied by a little white smoke. Both will disappear after a short while.

Catalytic converter  

The catalytic converter traps and converts pollutants before the smoke comes out of the tailpipe, ensuring that most of these do not get released into the atmosphere in their toxic versions.

Water can also come from a catalytic converter neutralizing toxic gases  

This conversion normally produces water vapor as one of the byproducts. Water dripping out of the tailpipe is taken as a sign that the catalytic converter is doing its job. 

Faulty pistons or rings 

One instance where water in the tailpipe is a cause for concern is if it is accompanied by either a burning smell or a sweet aroma. This usually suggests that there is a problem with the engine’s pistons or rings. 

Head gasket failure

Another warning sign is if, in addition to the water coming from the car’s tailpipe, you also notice bubbling in the coolant reservoir or if there are engine overheating issues. This needs to be immediately addressed, as it can lead the engine to stall in the middle of a drive and leave you stranded.    

Find more tips for beginner car owners at Philkotse.com.