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Why Is my Car Smoking White Smoke from the Exhaust

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Why Is my Car Smoking White Smoke from the Exhaust

White smoke coming from your car’s back is no good news, but it does not necessarily mean that you need to rebuild your engine. There can be many reasons for white smoke coming from the back of your car. Sometimes the white smoke does not mean anything dangerous for your car, but it is important to check it in case the problem gets worse. In this OneHowTo article we'll explain you what are the causes so you know why your car is smoking white smoke from the exhaust as well as some tips on what to do if you have this problem.

You may also be interested in: Why Is Water Coming Out Of My Exhaust Pipe?

Is it serious?

White smoke coming from the back of your car can be ignored if it is thin like vapor. This is probably coming because of normal condensation build-up in your car’s exhaust system. It is normal, nothing to be concerned about, and will disappear quickly.

But if the smoke is thick, it can be a big problem. It may be caused because the engine is burning coolant. This may be due to a serious issue, like blown head gasket, damaged cylinder head, or cracked engine block. These are costly repairs, and need to be attended to immediately. Even small leaks in the coolant may lead to overheating, and cause serious damage to your car’s engine. Coolant may also end up mixing with the oil, and thus causing serious damage to your beloved vehicle.

Causes of white smoke

Usually, white smoke comes from the back of your car when water or anti-freeze enters your cylinder, and the car’s engine starts trying to burn it with fuel. Actually, the white smoke that you see coming out is steam. Head gaskets and other special gaskets keep the anti-freeze from entering your car’s cylinder area. The cylinder is the place where the air mixture and fuel are burnt after compressing. Anti-freeze that enters the cylinder that then produces white steam that comes out from your car’s tailpipe area. The anti-freeze gets into the cylinder probably because the engine got overheated and the head gasket failed because of excessive heat. Due to this, anti-freeze was allowed to enter the cylinder, from where the problem started.

Causes of white smoke

What to do

If you see white smoke coming from your car’s exhaust, check and make sure that there is a proper amount of anti-freeze in your car’s radiator, and also the over-flow bottle.

Also check if anti-freeze has contaminated your car’s engine oil. You can check the engine oil dipstick, and also the under-side of the engine oil filler cap. If you see contamination with anti-freeze, which will look like a chocolate milkshake, you should not start your engine, and contact a mechanic as soon as possible.

If you continue driving your car with contaminated oil, it may cause serious damage to your car’s engine, which will end up in extremely costly repairs and replacements.

If you want to read similar articles to Why Is my Car Smoking White Smoke from the Exhaust, we recommend you visit our Car Maintenance and Repair category.

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14 comments
Denise maxwell
Your rating:
Damn !
Tshegofatso
Toyota Tazz 130 2002 Model is smoking black smoke when it's cold and is vibrating. After 10 minutes it becomes fine.
Aaron
The white smoke coming out smells like burnt oil at times but not all the time. It's a Audi A4 with a aftermarket turbo.
Ronnie
I was driving my meriva 1.3 cdti the Rev counter went into the red by itself and plumes ov White smoke I turned ignishion off but it kept going I stalled the car it stopped now when I try to start it it seems to be leaking diesel or oil from engine and will not start wt can this be
Takeya
I just got my car out the shop. I have a 2000 Saab 9-3 my engine been replace, my turbo been replace, my gasket been replace, my oil been change everything has been fix. So I drive away with in 5 min of driving my car and it started blowing out white smoke again why is that
jessy sonny ellingsworth
If the car has set for along period of time and the gas goes bad will it cause the car to smoke
shane
I just bought a 86 camaro rs and its been a nightmare. The car , so i thought, is leaking and burning oil. Well i walked outside this morning and theres a huge green puddle under my car (coolant) and the car is pushing white smoke out the tailpipes on acceleration , it has a real bad smell coming out with the smoke almost like the burning smell of when the vaccume gets caught on a string of carpet. And ideas on what could be wrong? Its burning / leaking about a 1/2 qt of oil a day
Gareth
... three things to think about ... a breach in the engine block or heads ... or pipe work that feeds it ... or with your comment on burning Oil when you say there is white smoke and you did not seem to suggest blue smoke - is the valve timing correct along with those leaks ? ... now it would be possible to pin what it is if you say - is the water and oil mixing as try looking at the expansion tank for a start ... if not you could try a pressure test on the heads by a garage for a small fee and if ok ... then check - is there water pressure when engine is running ... there should be a large water pipe that goes from the engine to the radiator ... after five minutes there should be pressure there when you try to squeeze it with your hand - if you can still squeeze it like it was from before you started the engine - then the water cooling system is not sealed ... check also to see if any heat is in the radiator to test for water pump activity ... as for the engine oil run the engine for 4 miles down the road ... turn off the engine and look for the Oil filter and place your hand on it and if it is extremely hot and the engine head or heads is only warm by then this will suggest anything from valve timing to lack of air to breach in engine - in most cases it is valve timing or lack of air ... but a breach in the head gaskets would send the heads very hot like the oil filter at the same time ... if it is just lack of air or bad valve timing normally the oil filter is very hot first ... whilst you are at it check the oil circulation ! ... have a look whilst the engine is running - do you notice oil wetting between the cam shafts and the cam shaft bearings if you can see that far with the oil cap off with the engine running ... as for water it is probably best to look for that hose leak and replace the hose and then for a week run a stop leak through it ... look at the radiator whilst at it to ensure no leaks there too ... then drain it out after that as it would have sealed everything else by then but ensure you buy a New Radiator Pressure Cap before you do any of that along with a New Water Thermostat ... then replace the spark plugs ... although they say these will indicate the condition of the engine - this is not always the case as it really depends on if the inlet manifold is clean and not being invaded by the the breather system ... check the valve timing whilst replacing the spark plugs - this will mean taking the cam covers off as whilst they are out - you will be able to rotate the engine in the direction it normally rotates - never try to rotate it the other way as this will encourage a slip of the valve timing if the tensioners are not holding properly as it were although most of the time they will hold anyway ... so if not a breach in the gaskets or heads depending on engine - then I hope this helps :-) ... on a final note about the amount of oil it is losing - look at the crank pulley and around the head gaskets and this is best done at night with a touch light or in a garage as you will see more ... a breach in the gaskets can cost that much in oil but so can the crank shaft pulley seal along with other things that seal the oil system - really depends on how far you travel per day but when you say a horrible smell is there - that would indicate it is inside your exhaust system ! ... meaning it is over heating for it to end up there even if there is no breach and is caused by bad valve timing say ... would be good to start with the pressure test to test those gaskets which a garage can do for you and the expansion tank like at the start of this reply ... if everything is ok then it shouldn't cost too much to solve - Hope this Helps :-) ....
Miss Hooi
I have just bought this new Mercedez C200d diesel engine since March 2016, only 3 months ago. Its start emitting white thick and smelly smoke from the exhaust after the third week. Complaints to the Mercedez dealer and they could not find any fault and said its could be steam and the Diesel Filter is trying to burn out new wax or any particles that has been there due to new parts. They told me to monitor it and its still emitting white thick smelly smoke on several occasion as this is the 6 times reoccurrence and could not find any sign of leak from the bonnet. Please advise me what should I do as not to void the warranty as Mercedez dealer keep saying its not any problem just steam, should I get a second opinion from another garage to look into this issue.
Gareth
... yes as Mercedes suggested - contamination of some sort ! ... sometimes because of new parts the engine exhaust gas output will be restored if it has been less than what it should have been before those new parts went in ... the areas to look at are - Engine Oil and Engine breathers and of course the Exhaust System ... assuming your water system is fine and there is no loss ... start your engine and drive about 1 mile at 30 to 50 miles an hour ... do not turn off your engine for the next check but have a piece of cloth you don't mind ruining as opening the oil filler cap if it is close to the cams can mean some splashes of Oil when you increase the revs whilst the cap is off ... open the engine filler cap whilst the engine is still running ... look inside ! ... if you can see heavy amounts of steam - that means the engine Oil is contaminated and will certainly mean a change but before you do try to find the cause as there will be little point changing it for the cause to contaminate it again ... now assuming like Mercedes say that there is no coolant leak and everything is fine including your Glow Plugs and fuel tank ... have a look at the breathers ... if you see cracks in the tubing from any of the sump or head breathers - this will lead to Oil absorbing air moisture from outside the engine ... the Dipstick should have a 'O' ring also ... believe it or not ... if it is the breathers then the dip stick will say everything is fine and as soon as you drain the Engine Oil out the Oil is saying something else as most of the moisture mixed with Oil will be sitting at the bottom if you drain it from cold and the engine has not run in some 6 hours say - if so make sure you find those breathers as if it does exactly what I wrote there it will certainly be them causing it ... there are two lines one from the sump and one from each engine head ... if you wish to resolve the problem without voiding Warranty then ask them to change the Oil and fix those breathers and ensure that all cam cover gaskets are replaced also - this is not anything to do with the Main Engine gasket as we are assuming they have checked that and it is fine ... check you receipts - if they changed the head Gaskets say - look carefully at what else did they did ... the cam cover gaskets in many garages are sometimes reused would you believe ! ... they will charge you for this but if they were meant to change those as part of the service then get them to rectify the problem because it is them doing it - it should not void the Warranty and is not that expensive no matter if they are rectifying the mistake or pay for the addition - depend on what service you asked for ... ask them also - is it on the correct grade of Oil ... if it is an older car or high mileage ... and it is running on say for example 5w 30 Engine Oil grade ... look at the hand book and if it can take higher ... you may wish to upgrade to 5w 40 ... ask the people that do the Warranty - can they do this ... what this does is it ensures the piston rings are sealed at all times with it being an older car - it is a common mistake to have it on less but do research what the car is meant to run on and learn the entire range of different grades of Oil your car can safely take ... this is particularly important if you do use detergent in your fuel as an additive ... a lot of fuel stations do sell additives in the fuels they sell ... if too much gets in to the Oil through the rings - can lead to that problem also as it will break down that Oil - if you have it on the correct grade then this will not happen ... do avoid taking it out of Warranty if possible because as Mercedes say this sometimes happens and all that is happening is the system is blowing out the contamination from previously before the servicing was done ... although if they have not suggested at an additional charge to change the engine Oil and Oil filter in the least sense after say 2 weeks - you may want to ask them why as it maybe sometim
gopal
i will be using Lancer petrol car, my car smoking white smoke from the exhaust and engine oil usage increased.
Gareth
... you may wish to have a full diagnostic inclusive of head gasket pressure test ... ensure that the pressure test is not done from the expansion tank but directly to the water inlet and outlet from the engine head to be sure that it is the Gaskets you are testing ... start there - hope this helps :-) ....
Gareth
... on the mondeo 2.5 litre v6 mk2 ... I experienced a coolant leak from a water pipe that is located from the water pump to the engine block - it fits between the engine heads ! ... This water pipe also is right next door to the Positive Crank Case Breather ... if both are leaking like mine did - it draws it into the Inlet Manifold when enough wetness is there for it to soak into the Crank Case Breather - otherwise known as Oil vapour Separator ... it is located right next to that water pipe between the two heads ... I very nearly had to bring both heads off but it was not hard to discover what happened after looking at the breather ... normally it is a sign of cracked engine ... cracked head or blown gasket but it turned out to be that on this occasion - a blown water pipe leaking into the crack breather causing it to smoke at first then disappear - this is the second time this has happened as the cause of the water pipe failure is down to the fact it is not perfectly round and the pipe is not able to fully grip it unless quick gasket is used ! ... having said that yeah you could say send it to be fixed but it is an old car - fix the roundness of that pipe later lol :-) ... I got lucky and it is rare for a car to be designed like that for that to be possible with the two pipes being so close to each other but ... on the other note about other cars if you notice vapour that disappears that was mentioned this can be a sign of two things ... too much detergent with advanced fuel added from a petrol station or if one has added too much to the fuel tank with not enough spark kilowatt energy power to fire it - the tell tale sign is you can smell fuel in the exhaust system and loads of water comes out of the exhaust under heavy acceleration but there is no white smoke but during warm up there maybe some vapour but it goes after the warm up period - if so change your Spark Plugs to a better rating that will more easily handle higher Kilowatt rating - do not adjust the gaps as they are pre-set these days ... typically speaking Iridium Power by Denso company or NGK Platinum Cone tips or better - the reason being is that they get wet unless the Spark energy is able to go that far in remaining with a good spark to avoid getting wet during warm- up ... if you have bad Spark Plugs you will notice strange things like misfiring hesitation on acceleration and during warm-up loads of water coming out of the tail pipe and vapour there at the end of warm up but disappears afterwards if you continue ... and the second possible cause is ... too much Carbon Dioxide emissions - beyond 6% at idol which is most noticeable at night in cold weather but seemingly is not there during the day ... this also means the ignition system is not suited to those emissions with the Carbon Dioxide levels being that high ... most of what is said on this page is spot on but I've added what I know - there are other causes that can puzzle even the most experienced mechanics unless a full diagnostic is done ... hope this helps :-) ....
Erika Van Greunen
My smartcar let alot of white grey smoke. And oil came the dipstick. Does not have alot of power. What can be wrong. We put in a new turbo.
Alba Charles
If the car is smoking white smoke from the exhaust and loses power, it might be that it is burning coolant, which could be a problem with the head-gasket. However, it is quite difficult to determine the source of the problem without seeing the car. Bring it to a mechanic for a complete checkup.

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Why Is my Car Smoking White Smoke from the Exhaust
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Why Is my Car Smoking White Smoke from the Exhaust