5 Causes of Car Blowing White Smoke from Exhaust

Last Updated on May 5, 2020

If you start up a vehicle with a gas engine and you notice white smoke blowing out of the exhaust pipe, there are a few reasons why this could be happening.

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One reason for white smoke is very common and completely harmless. But there are other times when white smoke is coming out of your car’s exhaust that you do need to pay attention to as it can be a sign of a major problem.

5 Causes of White Smoke Blowing From Car Exhaust

#1 – Condensation

white smoke blowing from exhaust

This is a common occurrence, especially in colder climates. When it’s cold outside and you notice white smoke at startup, then you probably have nothing to worry about.

When the warm or hot exhaust gases meet cold outside air, condensation and steam is a result. After a short amount of driving, the white smoke should lessen.

It’s common for drivers who have lived in a warm climate like California and then move to colder region to worry about this but it’s harmless and perfectly normal.

#2 – Coolant Leak

If you continue to see white smoke coming out of the pipe after the engine has had a chance to warm up or while accelerating, then your coolant might be leaking internally.

The most noticeable symptom of internal coolant leakage is when the white smoke is billowing out of the exhaust pipe and leaves a sweet odor in the air. If you the white smoke consistently comes out and the sweet odor smell is present, then it is definitely a problem with your coolant leaking.

The reason why coolant usually leaks is because there could be a crack in the cylinder head or even engine block. Even if the crack is small, the internal coolant can easily leak out and contaminate the oil of your engine. This is how the exhaust smoke ends up turning white.

The combination of the coolant and engine oil will create a milky appearance in the smoke. All it takes is for just a little bit of coolant to get into the combustion chamber for white smoke to be produced.

Once you have a low coolant level and a cooling system that isn’t being maintained properly, your engine will begin to overheat. This will cause your head gasket to fail because they won’t be able to seal properly when they’re overheated.

As a result, your engine will get worn out much faster and its internal components will get damaged.

#3 – Piston Ring or Valve Seal Leak

symptoms of bad piston rings and valve seals

Leaking valve seals or piston rings are another possibility when it comes to smoke. In this case, bad seals or piston rings cause oil to leak into combustion chamber which then mixes with fuel and burns. The result is a white or light bluish smoke that comes out from exhaust manifold.

If you want to fix this white smoke problem, the easy solution is to take your vehicle to the nearest auto body shop as soon as you notice it. But if you are trying to fix this yourself, never try to remove the coolant reservoir cap with the car still running because the engine will be too hot and it will cause you serious injury.

Once the car has had a chance to cool down, check the reservoir and see what the coolant level is at. If the coolant appears to be at the normal level, then you’ll need to have a cooling system pressure checked performed so you can pinpoint where the coolant leaks are coming from.

#4 – Bad Fuel Injector

fuel injector replacement cost

A faulty fuel injector, usually one that is stuck open or is leaking from the o-ring, will deliver too much fuel to the combustion chamber. This excess fuel cannot properly burn in the engine and instead comes out as white or gray smoke out of your tailpipe.

Replacing the bad injector (or its o-ring) is the solution.

The hard part is figuring out which fuel injector is bad so depending on vehicle mileage, many mechanics will recommend replacing all the injectors since they’re not very expensive in most cases.

#5 – Incorrect Injector Pump Timing (Diesel Engines)

A diesel engine requires precision timing and fuel pressure of the injector pump. When the timing is not what it’s supposed to be, your engine will essentially be running rich which will cause fuel to not completely burn and instead exit out of the exhaust as white or gray smoke.

 

Comments

  1. Thank you, the info was helpful.
    Is there any lubricant or anything else that can be mixed with fuel or engine oil or coolant to reduce the white smoke emission.

    Thank you!
    JA

    Reply
    • I have this particular experience in my ew0 engine. In fact one could watch the coolant sink into the engine as it is refilled. When the engine is running the smooth gets thick white though slightly clears When the engine gets hot. I really need help. Engine from the dip stick does not appear to be mixed with water. I also notice loss of engine power while in motion.

      Reply
    • Also it does not have a sweet smell at the exhaust it smells like gasoline could this be a fuel injection problem? Could it be because the person that put the radiator and just clip the copper part of the transmission cooler line

      Reply
    • Hi,I have a MAN TGA,26.480,I changed all the injectors,all the filters including the tube filters and did all the head gaskets but the truck is still pushing out white smoke when accelerating,it smells like unburnt fuel…can someone help?

      Reply
    • my vehicle is having this issue right now. mechanic thinks its a seal sticking to piston, which results in a new motor 🙁 Apparently Chevy has a big problem with this from 2007- 2012 era.

      Reply
    • Okay how about brand new water pump and everything belts squeaking little bit and it’s smoking I don’t know why what can be the problem

      Reply
  2. I recently had my car in for a major repair.
    Its Mini countryman Cooper S with 4WD – it needed a new timing chain and oil pump.
    I had to Take it back to the garage because they hadn’t changed a seal and it was leaking oil. I had also flagged to them that it was intermittently billowing white smoke.
    It appears they did not address the issue with the white smoke from the exhaust.
    It’s intermittent and seems to be most obvious when taking off from a stop, or reversing into a space – so when the engine is under load. I can’t say it’s a sweet smell, but there is certainly a smell!
    Could this just be a bad seal? I know for sure that they are going to awkward as they had real problems with this initial repair – I think they bit off more than they could chew and I suspect they have barely broken even on what was a very time consuming and expensive repair.

    I’d appreciate any suggestions.
    Many thanks

    Reply
    • It does sound like intake valve seals to me. When idling, the vacuum pressure is higher and you are sucking in a bit of oil. When you give it gas (from a stop or when reversing), the oil gets in the combustion chamber and quickly burns off. It would appear as a blueish/whiteish smoke.

      Reply
    • My car blows out a large cloud of smoke when i start it for the first time everyday and then stops but the area around where my belts areunder the hood is making a clattering noise

      Reply
    • Hey Stewart, I have Countryman S 2012 with the exact same thing white smoke at idle and go. Did you fix it?

      Reply
  3. If I start my car it will not show any type of smoke but if I am driving with higher speed or low speed of about 50 km/h it will show a small white smoke emission from the tile end exhuth please I need to know the condition of my car ,remedy and the possible solution

    Reply
    • I recently just got a new radiator put in my 99 Jeep Cherokee as a new water pump also from overheating when I came back the next day to fix it because I was broke down at the store it would not fire up only with jump start and pumping the gas as soon as jumper cables were taking off car shut off now it will crank over but there is water or fluid coming out of the tailpipe and white smoke what could this be the person that put the radiator in cut the transmission cooler line could this be the reason

      Reply
  4. So what could be problem when the smoke only come when you start the engine and AC on in idling time 4hour or more, and accelerator pressing white smoke coming.half km driving there is no smoke.

    Reply
  5. I did the heard and changed the valve stem seals, petrol pump plugs, oil filter and timing belt on a Mitsubishi lance glx 1.6 2004. After that there is a smoke coming out when I start the car and once the engine is warming it died down. What coup be the reason?

    Reply
    • It’s likely normal due to some oil that got on parts. You should notice less and less smoke until it final burns off completely.

      Reply
  6. When I accelerate my car (Mitsubishi Galant), often miss-fires and a puff of white smoke comes out…then she takes off.
    I recently had the oil pan replaced and the guys told me my spark plugs, timing belt, and some pump need replacing too. Will this solve issue?

    Reply
  7. Hi my mini one seems to smoke when it gets up to temp and idling but not when driving and it’s not overheating and there are no warning lights present . Should I be worried ?

    Reply
  8. I have a ford mondeo 2.0 diesel. Every now and again about once every 3 weeks or so I have either smoke pouring from the engine for about 2 minutes if I am stationary or if I am moving the car coughs a little and I get plumes of white smoke from the exhaust for about 5 seconds then it all clears. I have no other issues and dont lose any oil and it is serviced very regularly but the smell from the smoke in the engine is burning oil. Like I say it’s not constant but worrying and there is no oil on the floor at all

    Reply
  9. My 2008 GMC Sierra has 180,000 miles. I crank it up in the morning and it’s white smoke really bad that comes out but burns off fast. If I park it say 3 hours it will smoke but less.

    Reply
    • Check your oil level. You probably have a small oil leak in the combustion chamber which burns off from the heat after starting the car. The longer the car sits, the more oil drips in there so you have more smoke. This is assuming the smoke is a white/blue-ish color.

      Reply
  10. when i start my car the the car accelerates low and sounds like its struggling after it blows out the grey smoke it then goes back to normal? what do i do to fix it…

    Reply
    • I get white smoke on starting but dissipates after about driving 800m
      changed the stem valve seals for new ,oil change plugs e.tc. but still the same.

      Reply
  11. I just recently put a used motor in my SUV 04 Land Rover,due to the other one having a crack in the engine block. The older engine was leaking coolant in the oil so bad that water would even flow out of the tail pipe, especially if you revved up the engine. Of course the oil was white where the coolant was mixing with it. Now I have what seems to be a good motor put in it after about 8 months. It seems to run well and in checking the oil, there is no coolant mixing. However, when the engine gets warmed up, it does begin to blow out some white smoke. Depending on how it sits some times it is thicker or really thin. I drove it down the road and did not see any smoke. When I drove it back and turned around, it blew out some white smoke. I revved it up some and it seemed to thin out and at times seemed to almost stop smoking.
    Could this be some coolant/moisture that is still setting/puddled up in the muffler and exhaust from the previous motor and once the system gets hot, it is evaporating the left over water? The motor runs smoothly during this whole time.

    Reply
  12. Sometimes after I run my AC for awhile while idling around work or sitting somewhere I turn off the engine and when I come back shortly after and start up the engine a decent size puff of white smoke comes from the exhaust. Also today after that happened a low coolant light came on and I went to check it out right away. Coolant looked fine and light was off when I started engine back up. Could this just be condensation build up or do I need to investigate more?

    Reply
  13. Ok i have a dodge Durango and it has a different motor in it the size of the motor is v8 one size smaller of the 5.9 and I got white smoke when I start or it might be a bluish white but it’s not really thick and here recently when I drive after I let it warm up completely. I have noticed that when I’m going down the road it has a little trouble shifting at the 30 mph range the rpms gets to 3000 rpms and I can let off the gas and it will shift but then when I get to the 40-45 mph it does it again it will shift on its own @45 mph but then when I give it gas it starts to shimmy like the motor is straining but not all the time. I Had thought it was bad gas so I used fuel injector cleaner,gas cleaner, and other stuff that i thought would work but it’s still doing it my question is what should I do to find out what is wrong with it cuz its my only way back and forth to work thank you in advance for your reply

    Reply
  14. F350 diesel 166k white smoke on startup smells like diesel. Stops after warm. From what I’m gathering from this article there’s an injector problem correct? Please respond with advice/suggestions. Thank you for your time.

    Reply
  15. Hi , my Renault is using a lot of oil and all of a sudden a lot of white smoke is coming from the exhaust when starting the car . What do you think it could be ?

    Reply
  16. Another cause: My VW Golf Mk4 Diesel was difficult to start and giving off lots of white smoke on startup. The cause was the temperature sensor. Replacing this fixed the problem.

    Reply
  17. I recently ( not even 45 days ago) purchased a 2017 Chevy Equinox. I noticed right away that my dash said 23% oil. I called the dealership. I was told it had a oil change. I have not checked the oil yet. I am waiting until it cools off. I noticed a white smoke coming out of my engine. I have no lights on my dash at this time. What can be causing this?

    Reply
    • The “23%” refers to oil life remaining which is completely normal. Most newer cars monitor this in some way. Checking the oil level should be the #1 priority but you definitely have some type of leak that’s causing the smoke when it makes contact with hot engine parts. Check the levels of all fluids to find the issue.

      Reply
  18. There is a white could of smoke that’s coming out of my exhaust, but that only happens some times after starting my vehicle. There is no sweet smell, it smells like petrol and there is a lot that comes out. I does not always happen but if you can give me advice I would really appreciate it.

    Reply
  19. Thank you for the I have a Toyota diesel and the white smoke seems to have some odour and thick it seems I may have problem with a coolant.

    I am taking to a mechanic.

    Reply
  20. I have a dodge nitro it has set few months when I started it cloud of white smoke (allot) came out exhaust, went away after driving it, but I have started it twice since and white smoke come out at first n goes away

    Reply
    • Sometimes cars blow a little white smoke when they’ve been sitting for a while. This is not cause for concern. If the vehicle continues to blow white smoke even after it’s warmed up, this could indicate a head gasket failure. This is typically accompanied with a sweet smelling exhaust.

      Reply
  21. I need help when I start my Peuget 308 gti in the morning while it get warm white smoke come out, but when you drive it goes off and the car is normal for driving no smoke. What could be the problem can somebody advice.

    Reply
    • Unless the white smoke also smells sweet this sounds normal, especially if you’re starting the car on a cold day. Condensation will build up in the exhaust system and create a white cloud of smoke on startup, but if it goes away as your car warms up and you are experiencing no other symptoms then I don’t think this is cause for concern.

      Reply
  22. Hey, my car is having a hard time starting and when it does it spits out white smoke. what could be the cause? It is a 2005 Toyota Scion if this is needed to troubleshoot. Thanks!

    Reply
    • Some cars smoke on startup due to temperature or from condensation, especially after sitting for a long time. I would take your car to a mechanic for a (likely quick) diagnosis if you continue to run into trouble.

      Reply
  23. Hello,
    My Opel Meriva Z16XEP has white smoke and the coolant has some thick whitish thing. It also has a Lil rough idling

    Reply
    • The symptoms you describe sound like it could be a head gasket leak. I would perform a leak down test so you know for sure before tearing anything apart.

      Reply
  24. My 2001 Honda Accord has a thick white consistent smoke coming from the exhaust & also the hood(while idiling) when starting the car up & for awhile after, no sweet smell emerges only a strong gas odor, lack of power & acceleration are also issues, what can the issue(s) be??

    Reply
    • It sounds like a head gasket failure. Since a head gasket replacement is an expensive job, I would verify that with a leak down test first so you know for sure. A leak down test is about $200 at a shop, while a head gasket replacement is anywhere from $800-1200.

      A leak down test is pretty easy to perform yourself if you have an air compressor and are looking to save some money. You can probably rent a leak down tester from your local auto parts store for free.

      To perform the test, all you have to do is screw one end of the tester into each spark plug hole, hook the other end up to a source of compressed air, then watch to see if any air leaks into the cooling system. You will see this either out of the radiator cap or the coolant overflow reservoir.

      Note that this test must be done while each cylinder you test is on its compression stroke, so you’ll need some way of turning over the motor (a wrench and the appropriate socket for your crank pulley bolt).

      Do not remove the radiator cap while the car is hot. This is dangerous and could burn you.

      Reply
  25. I got home after a day out to find a bad leak in the radiator,next day I
    Replaced it with a new one got the antifreeze to the correct level,on
    the following day I started the engine with some difficulty and found
    white smoke billowing out of the tail pipe,I have no sence of smell so
    I can’t help you that way. I would be obliged for your opinion. Thank you.

    Reply
    • Did the antifreeze leak out onto the ground, or did it mysteriously disappear? With the information you’ve given me, I’m inclined to believe it’s a leaking intake manifold or head gasket due to the white smoke. These leaks will likely be internal and probably won’t leave a puddle of antifreeze under your car.

      Does the antifreeze level continue to drop with the new radiator? If so, the problem lies elsewhere.

      Reply
  26. My Ford Ranger 2.2 TDCI 2017 model having a problem with a smoke, vibrating and without and there is a smoke that also goes to air filter from the engine.

    Kindly assist

    Reply

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