Water Coming Out of the Exhaust Pipe? (Should Your Worry?)

Most car owners have probably noticed that water drips from the exhaust pipe at idle. But what does that mean and should you worry? Let's find out!

Water Coming Out Of The Exhaust Pipe

Your car’s internal combustion engine releases exhaust gas as part of its normal operation. If these gases were to remain in the engine, it could be very dangerous. However, it is just as alarming when you see something other than gases coming out of the exhaust, such as water. What are some of the causes of water coming or dripping out of the exhaust?

In some cases, the water is considered a normal byproduct of the operation. However, there are other times when you should take the leaking fluid seriously and have it checked out. Let’s take a look at the possible causes:

The most common reason for water dripping from the exhaust pipe is just normal water condensation. Smell or taste the water from the exhaust pipe and if it does not smell or taste sweet, there is probably nothing to worry about. If it smells sweet, it’s coolant.

These causes are the fast list of the main causes of water dripping from the exhaust pipe. Let us take a more in-depth look into the most common causes:

Water is Dripping Out of Your Tailpipe Causes

1. Water Condensation

Smoke From Exhaust

The most obvious reason you will see water coming from the exhaust is due to condensation. This process is completely normal and happens for a variety of reasons.

During the internal combustion process, carbon dioxide, nitrogen and water vapor are formed. As the gases leave the combustion chamber, gases are being mixed with the water molecules. As the engine cools, water condensation often becomes visible, especially from the tail pipe. 

If the water droplets stop after a few minutes, there’s nothing to worry about. Otherwise, you might have a larger problem on your hands. 

2. Catalytic Converter Condensation

Catalytic Converter 1 E1609777534665

As with the condensation coming from the engine, you may also be dealing with water vapor from the catalytic converter. Remember, the cat is changing the chemical makeup of the gases, thereby creating more water molecules.

In the conversion, water vapor can make its way out of the tailpipe. As with the previous condensation, this should resolve itself within a few minutes and is considered a normal function of the exhaust system. 

3. Head Gasket Failure

Head Gasket On Engine

While the previous reasons weren’t anything to get alarmed about, a head gasket failure is. If the water coming from your exhaust is due to a blown head gasket, you have a serious problem.

The blown head gasket often comes with white smoke coming from the tail pipe and water droplets. You may also see air in the coolant reservoir or your engine might begin overheating. Either way, you want to get the problem resolved quickly before you need a complete engine replacement. 

RELATED: 5 Symptoms of a Blown Head Gasket

4. Defective EGR cooler

Volkswagen Egr Cooler

Some newer car engines, especially diesel engines, use an EGR cooler to cool down the exhaust gases before entering the intake. The coolant cools the exhaust gases, and this part can crack. If the EGR cooler cracks, it can cause coolant to come into the exhaust pipe and drip from the tailpipe.

If the water coming from the tailpipe smells sweet, it could definitely be caused by a broken EGR cooler if your car is equipped with one.

5. Defective Pistons or Rings

Piston Ring Function

Worn-out piston rings or a bad piston only cause water to come from the tail pipe if the head gasket is also blown or there is already condensation in the exhaust. Additionally, bad pistons and rings can lead to other symptoms.

You might notice a sooty exhaust, oily residue coming from the exhaust or blue smoke. Either way, you don’t want to continue driving with bad pistons or rings.

RELATED: 4 Symptoms of a Bad Piston Ring

Cost to Fix Water Coming from the Exhaust

If the water is caused by normal condensation, there’s nothing to repair. However, both a blown head gasket and defective pistons or rings should be dealt with immediately.

The cost to repair a blown head gasket is between $1,000 and $2,000, but not because of the parts. Instead, this repair takes a long time, leading to higher labor charges. Additionally, the cost to replace defective pistons and rings is between $1,000 and $5,000, mainly because of how labor-intensive the job is. If either of these situations is left unresolved, it will lead to needing a complete engine replacement. 

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Written by:

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.