6 Reasons Why Water is Coming From Your Car Exhaust
Seeing water drip from your tailpipe can be alarming but isn’t always serious. In some cases, condensation buildup is normal. In others, it signals major engine issues like a blown head gasket.
This article explores the possible reasons for water in your exhaust, from harmless to hazardous, so you can assess the severity and know if repairs are needed.
Read Also: 6 Reasons Why Oil is Coming Out of Your Exhaust
When Water From Your Exhaust Is NORMAL
Water from your exhaust is pretty normal, so long as it’s not too much. Let that be what you take away from this article—if nothing else.
#1 – Natural Water Condensation
The internal combustion process is not without its issues, as there are sometimes pollutants that form throughout. The main three are water vapor, nitrogen, and carbon dioxide.
When you turn on your car, both the water vapor and the CO2 mix together. Then, once you’ve reached your destination and powered down your vehicle, you’ll begin to see this water vapor come together and collect on the inside of your exhaust tips.
You might notice some drips here and there, but this is nothing to be concerned about and just a part of normal car operation. Condensation is the cause of 99% of water-related exhaust issues.
#2 – Catalytic Converter Producing Water Vapor
Oh boy, catalytic converters—or “cats”—are just so amazing, aren’t they.
So amazing that jokers are trying to steal them right out the bottom of your car the moment you leave your rig unattended. A few minutes, a sawzall, and a very motivated gentleman will have your car sounding like a racecar all for free.
Sure, you can drive without a catalytic converter, but you’ll probably get dinged by the annual emissions test or the police. Best to keep one on there.
In any case, a cat removes the toxins created during the internal combustion process, and creates a bit of water vapor as a byproduct of the process. This water vapor may accumulate on your exhaust tips and drip from here and there.
The takeaway is that normally, that there’s nothing to be worried about when you see drips of water coming from your exhaust tips—provided it’s very minimal.
Potential Issues That Can Cause Water From the Exhaust
#3 – Head Gasket Failure
When your engine gets REALLY hot, things tend to warp. In a lot of cases, this is the result of a blown head gasket. Your head gasket is like the VIP bouncer of your engine, keeping fuel, oil, and coolant from mingling at the party. When this bouncer fails at its job, you’ve got a recipe for disaster.
If you notice more water (perhaps a cup per hour) coming out of your exhaust, you might be in for a bad time. Inspect the liquid. Is it clear? Or is it a bit brackish and opaque? If it’s a bit muddy to look at, it’s probably coolant. If this is the case, immediately turn off your vehicle and pop the hood.
Remove the oil filter cap and take a peek inside. Look milky? Green? If so, these are the tell-tale signs of coolant mixing with fuel. Now you’ve got fuel that isn’t burning as well, oil that won’t lubricate, and coolant that doesn’t cool! You’ll end up with milky, stinky liquid exiting your exhaust pipe, and you should take your ride to the mechanic ASAP.
Replacing motors is very expensive—believe me—and it’s something you want to avoid at all costs. Please ignore the kid down the street saying “Motor swapping isn’t bad, bro”.
#4 – Cracked Engine Block or Cylinder Head
Let’s talk about the engine block and cylinder head. These are crucial parts of your engine, and when they crack, you’ve got a serious problem on your hands. This usually happens because your engine overheated badly or something physically damaged the engine.
In rare cases, using water instead of proper coolant in extremely cold temperatures could cause freezing and expansion, potentially leading to cracks. But with modern antifreeze, this is pretty uncommon.
When coolant leaks into the combustion chamber or exhaust system due to these cracks, you’ll see water or steam coming from the exhaust. You might also notice your coolant level dropping, your engine running hotter than usual, and your car’s performance taking a nosedive.
If you suspect this issue, get ready for a hefty repair bill. Fixing a cracked block or head is a major job, and it’s definitely not something you want to ignore. Trust me, your wallet will thank you for catching this early.
#5 – Bad Pistons or Rings
Generally, piston and piston ring failure will not cause water in your exhaust unless the head gasket is also blown at the same time. One way to diagnose whether or not your rings and pistons are blown is to look for black sooty residue or an oily film at the tips of your exhaust.
You may also notice unusual engine noises, a sudden loss of power, increased oil consumption (please check your dipstick or dip meter (WHY BMW?), and overheating as indicated by your temperature gauge. While you’re checking for these issues, keep an eye out to what kind of and how much smoke comes out of your exhaust when you start up your car.
This is less granular, but if you’re trying to specifically diagnose whether your piston rings have failed, keep an eye out for a dark blue/gray color to your exhaust when you are running your engine. This means your piston rings have failed.
If you’re replacing your head gasket due to water in your exhaust, best to check out those pistons and rings while you’re at it.
#6 – Failing EGR Cooler
Now, let’s chat about the EGR (Exhaust Gas Recirculation) cooler. This little gadget is all about recycling and reducing emissions. It’s mostly found in diesel engines, cooling down exhaust gases and sending them back for another spin through the engine.
But when this guy ever develops a leak, it’s like leaving the garden hose on in your engine. Coolant starts sneaking into the exhaust system, and suddenly your car thinks it’s a steam engine from the 1800s.
You might notice white smoke from your exhaust, your coolant mysteriously vanishing, and your engine running way hotter than normal. While it’s not as catastrophic as a cracked block or blown head gasket, it’s still a “get yourself to a mechanic” situation.
Ignore it, and your wallet might start crying louder than a teenager who lost their phone.
Diagnosing the Issue
A lot of the diagnosis can be with your two original tools—your hands and your eyes. (let him cook!)
First, start up your car from cold and go out back to observe the exhaust tips. Is there a steady flow of water coming out? If so, turn that car off. Then, go back up.
Are there just a few drips? It’s just water condensation and you’re probably safe to drive the car, so long as there’s no other issue unrelated to the exhaust that you’re ignoring.
The Short Answer
For 99% of cases, water dripping from your exhaust is going to be caused by normal condensation, and is not something to worry about. However, if it’s a significant amount of water, have that car checked out by a professional.
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I have a Peugeot 208 GTI 2014. Coolant needs top up constantly, white steam coming from exhaust, also exhaust smells sweet when running for a while. Can i see if gasket is blowing through 1 of my sleaves with a pressure test? If i pressure test my cylinders? Don’t want to take it in for new head gasket as it is very expensive, not alot of workshops work on Peugeot’s here in South Africa. Want to be dead sure before sending it in for any tipe of repairs. Other tipe of tests i could do to determine if my head gasket has blown? Or find out where my coolant is disappearing to?
Thanx in advance
Yeah, probably the best test for you would be a leak down test. This is a sort of pressure test that pumps compressed air into each of the cylinders. You can measure “leak down” (how much each cylinder leaks), but where the air is leaking can tell you a lot about your engine.
If you see air bubbles in your cooling system while performing this test, chances are really good that you have a head gasket leak. It’s possible to have a cracked head or cracked block and see air bubbles in the coolant as well, but these issues are less common than a blown head gasket.
Hello, just wondering if you could tell me if this is a serious enough issue. where I shouldn’t go anywhere until it’s fixed or figured out? Don’t want to end-up stranded. Recently my son changed my spark plugs for me but, they were soaked in oil, he of course told me what he thought might have caused this, we cleaned up the excess oil, put new spark plugs in, but when starting it white clouds of smoke came out and now there is water/oil mix maybe? coming out of the tail pipe. What could be the issue now? Not safe for me to drive? leave me stranded?
What makes you think there is water/oil mix? Just the white smoke?
How far are you planning to drive the car? There’s really not enough information for me to say if the car will break down or not. More troubleshooting is likely needed.
Car was recently serviced. Asked for coolant drain and replace. Now it seems the coolant level is dropping rapidly for some reason. Oil looks normal. Water looks normal – some signs of bubbly foam. Engine is running smoothly and there are no signs of any water leak other that at the exhaust which is probably just condensation of exhaust gases. Any ideas on what’s causing the drop in coolant level ?
Sounds like something is leaking. You could have a coolant leak even if you don’t see anything. Sometimes a leak will show up as white streaks around the source of the leak. I’d take it back to the shop, tell them the problem, and ask them to take a closer look. Mistakes happen, and they can double check their work. Shouldn’t cost anything.
Hi my bmw 328i isn’t loosing coolant no overheating..but white smoke from exhaust even after driving for 30 minutes, it’s -3 Celsius outside. Is it normal
In cold temperatures, yes that’s perfectly normal. You will see a lot of white “smoke”, which is probably actually condensation from the hot exhaust against the cold air. It’s just like when you see fog from your breath in those temperatures.
Hi it’s my daughter s car ford focus 1.00 ltr eco boost. Running hot loosing water through exhaust expansion tank level dropping no leaks anywhere except exhaust
Is the car overheating? Any white smoke? You can do a leak down test to help narrow down where you’re losing water. Could be a head gasket failure. I don’t know for sure if the intake manifold has water jackets on this model, but if it does you could just need a new intake manifold gasket.
Probably best to take the car in, have a shop take a look and see what they say.
I adjust timing polo 1.6i now it dont idel and petrol smell
Double check your work, and make sure it is timed according to factory specifications. Sounds like some of the fuel isn’t burning completely because the timing is off.
I have a Hyundai getz that is spraying water out of the exhaust :(. I believe the head gasket was welded before I bought the car. The car has given endless problems, from jerking, to cutting out, to not starting. Now the problem is to start it and when it does start the water comes gushing out the exhaust. What do I do?
Is there any white smoke, or just water? If you see water alone, it does not necessarily mean there is anything wrong with the car. The best thing you can do is have a mechanic look at the car in person. It’s hard to describe how much water you’re seeing over the internet.
i have a slightly smoky exhaust with white fumes whenever i start the car and it disappears with time. there are few drops of water leaking out of the tail pipe as well occasionally. don’t know if it calls for concern
It’s probably not cause for concern if that is the only odd thing you notice, especially if it is cold outside. I would be more concerned if the car was also overheating, running low on coolant, or losing oil.
Water dripping out of where my exhaust pipe where they come together as one. Dripping fairly heavy. Something I need to be concerned about ?
Sounds like you may have an exhaust leak, for water to drip out of the middle of the exhaust like that. Are you sure it isn’t water coming from above the exhaust and following the curvature of the exhaust pipes?
Best to get it checked out so you know for sure.
when I rase my car in the morning smoke is coming out ,and water is still coming out of it, but when is working the smoke we disappear
Is it cold outside? Sometimes vehicles appear to smoke a bit when it’s cold outside just because of the condensation. It could just be the hot exhaust interacting with the cold air around it.
If you’re worried the smoke is excessive, it won’t hurt to have the vehicle inspected.
I have a F150. A year ago had the trans rebuilt. Just after that was having issues with running very rough. Took to a local shop and replaced everything ‘running’ related. Turns out it was bad gas from being parked for so long. Dropped the tank and emptied almost all the bad gas. Reinstalled tank and filled it with premium and octane booster and stabilizer. Start it once a week and sometimes on the road. A couple of weeks ago started running very rough, even more than usual. This morning started it up to run and noticed ‘drainage’ out of various joints in the exhaust system and I mean drainage. Felt clean, no oil, no antifreeze and no smell. What’s up?
I’m not sure. Are they coming out of joints in the exhaust like you have an exhaust leak and water is leaking out of the holes? I’m not sure I understand.
Steam like vapor from tailpipe old car 2000 Atos had headjob piston rings changed not coverheating no cracks seen but still vapor smoke cno smell and drops of water from exhaust what can it be?
A little bit of water from the exhaust is normal and no cause for concern. Does it look like smoke?
Mine is, I usually observe vapour and water dripping from the tailpipe particularly when the weather is cold. I also feel if oil is coming out as well but I haven’t observed such anyway
If its like 5 degrees celsius and quite moist out not raining, could that cause water leaking from my exhaust? I didn’t wait to see if it went away because it felt like gas on my hand but didn’t smell like it, smelt like nothing.
Yes, this is probably not a cause for concern.
Just had a blown head gasket in January2021, the cylinder head was replaced and the car was driving well, now excessive water is coming from the exhaust when I start the car, I checked the oil cap it looks ok. What could it be? Its a BMW 318 face lift 2002
I don’t know. Under some conditions it’s perfectly normal to see a bit of water coming from the exhaust. White smoke would be cause for concern. If you’re worried the head gasket has blown a second time, you could do a leak down test to help you confirm this.
You have a clog in your coolant system and the water is escaping as a vapor through your radiator cap. More than likely your radiator is clogged up from too much water and not enough antifreeze in the system
So I have to ask where all of my coolant goes?
Not in the oil Pan nor tans pan
Bubbles and pressure from a cool system
Engine clatters and loses power
Have I went too far with my problems?
I’m not sure I understand. It’s probably best to bring it to a shop for a diagnosis of the issue.
Your pistons and rings are not what’s causing water vapor to come out of your exhaust no matter what. What you mean is, your head gasket is bad that’s the only reason why water should be getting into your exhaust other than normal, than normal condensation.
Good catch, thanks. You are correct: in the case of bad rings, it would actually be oil coming out of the exhaust, not water. I’ve updated the article.
If I have a blown head gasket then wouldn’t my oil be milky?
Not necessarily. It depends on how the head gasket is leaking. I have had a blown head gasket without any symptoms other than occasional overheating.
Is that something to be worried about?
Water vapor from the exhaust? Usually no. Head gasket failure? Usually yes.