Tips from Used Car Advisor

Car Advisor Tamotsu Todoroki

Hi, this is Tamotsu Todoroki. I am a car advisor of
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Water? Petrol? Something Comes Out from Exhaust - Vol.167

If you see some form of liquid, whether it's water or petrol, coming out of your exhaust pipe you should first determine what it is and if it's dangerous before panicking. There can be a few different reasons why there's water or petrol coming out of your tailpipe and some are not problematic at all while other can be very serious problems. Follow the set of guidelines below to figure out how serious your problem is.

If you have water coming out of your exhaust
In most of the cases, if there is water coming out of your exhaust pipe it should be accompanied by a white smoke. This is a good thing as it could help you determine your problem easier and fix it accordingly. Luckily, most of the times when there is water coming out of your exhaust pipes it's not a problem as it is just condensed water (usually happens during colder days) that formed inside the exhaust system. You can confirm this if there is white smoke coming out of the tailpipe, but it's very thin and it resembles vapor. This issue can be easily fixed if you let the car running for a few minutes (the smoke should become colorless) and if this happens, you have nothing to worry about.

On the other hand, if the car has been running for a few minutes and the white smoke coming out of the exhaust pipe is very thick, it could represent a more serious problem with your engine. Most likely, there is a blown head casket, cracked cylinder head or a cracked engine block that is letting water slip into the engine and into the mixture, resulting in the white smoke and water coming out of the exhaust pipe. If you suspect that you might have one of these issues it is very important to get your car checked out by a specialist mechanic as soon as possible. Those are all very serious problems that could develop into even more expensive repairs if they aren't taken care of.

If there is petrol coming out of your exhaust
If you have petrol coming out of your exhaust pipe, you will probably notice that there is also black smoke coming out. If this is indeed the case, then it's a sign that there is an incomplete burn in the combustion chamber. This is caused by excess fuel in the fuel/air mixture and it can be cause by a few different parts failing. Most of the times, it's not a very serious problem and it's caused by a dirty air filter that hasn't been changed for a long time and it cannot supply the necessary air for the mixture.

Changing the air filter is a very simple operation and you can do it in less than one minute. If that doesn't fix your problem and there is still petrol/black smoke coming out of your exhaust, you are probably looking at more serious issues with your engine. The most likely parts causing these problems are a leaking fuel injector, a fuel regulator that's stuck closed, or a restricted fuel return line. If you have any of these problems, they are quite serious and you need the help of a specialist to fix them. You should do it as soon as possible so the problem doesn't get any worse than this.

Get professional help
Whether you're having water or petrol coming out of your exhaust it's important to have your car checked by a professional. If you ignore the problem you can end up with even bigger problems along the line and you will be playing with your own safety, so be smart and get professional help.