My Engine Is Blowing Smoke! What Does It Mean?

My Engine Is Blowing Smoke, What Does It Mean?

So, you put the pedal down and a cloud of smoke can be seen. That’s not good. But what does it mean? Well it depends. Some small amount of smoke may not be a fatal sign in your motor, but too much can be sign things are not well.

Let’s deal with petrol or gasoline type motors and consider some of the symptoms that will help us tell how bad things are.

Firstly how much smoke is your vehicle blowing? When did you notice it?

  •  If you noticed the engine smoke in the rear view mirror. Then it can be a very bad sign. Generally there has to be quite a bit of smoke for you to see it in the rear view mirror! If it wasn’t you that noticed it and someone else has seen it and alerted you, or you saw your own car under heavy acceleration blow some black smoke, it can simply be over rich mixture. This will usually be a puff of dirty black smoke which only really shows up under heavy acceleration. The injectors or carburettor are pushing more fuel into the engine than can be easily burned all at once. This may be no real problem.

What colour is the smoke?

  • If it is blue or blue-white in colour, then it can be another not so good sign. If there is blue in the engine smoke, that means it may be produced from burning oil. Whereas if it is more of a black smoke it may be over rich mixture under heavy acceleration as outlined in the previous point.

 When did you notice the smoking motor?

  • If it is at any time the vehicle is under load or accelerating then this once again may be a not so good sign. If it also seems to get worse as the engine gets hotter. This is also not so good

How is your engine oil holding up?

  • If your oil needs topping up often and there does not seem to be a lot of fresh drips of oil on the ground after parking your car for a while. Then this is a pretty strong indication the oil is going somewhere else than on the ground.

Does the engine seem to be a bit lower in power than it used to be?

  •  If the engine seems to not quite have that same ‘zing’ as it used to, then it could be re-enforcing our oil burning concerns. An oil burning car engine will lose power generally. This can make the car feel sluggish, especially under load. Often this is most noticeable up a decent sort of hill. If it is really feeling like the vehicle is working hard getting up a decent hill, then it is a sign something is not right.

Is the engine running a bit hotter than it used to?

  • If you have a temperature gauge and it seems to have crept up from where it used to be by a few degrees then again this can be a sign we have a tired engine on our hands. Once again this heating will be more pronounced in the up a decent long hill type scenario. If you notice the gauge creeping up as you climb, when you have not noticed it before then this is a sign the motor is not performing well under load.

Is the motor making more noise than it used to under load?

  • Once again, we are on that hill and the motor seems to be clattering, or making more noise than it should every time we push it.  The smoke is there and the rattle is not good.

Does the engine fume when you open the oil filler cap?

  • This can be a good test. But of course it is not wise to do this with a hot engine. If you are not confident to do this step leave it to a professional. Start the engine up and leave it to idle. Loosen the oil filler cap gently. Then remove it completely. If you notice a lot of fumes and pressure coming out of the cap this is also not a good sign. If the fumes look contaminated with smoke too then its a very bad sign. Basically there should be very little ‘fumes’ blowing out of the motor in a motor that is in good condition. There will always be some, but there should not be a lot. Remember to fit the oil cap back in place and clean any spots of oil that may have come out with a rag. Note that the engine may stumble a little bit as you open the cap as the pressure change may affect some controls hooked up to the engine.

 How many miles or kilometres has your engine done?

  •  If you are noticing some of the other signs listed previously and your engine has done a lot of kilometres then this is a big re-enforcer to our diagnosis. If the vehicle has done quite a few hundred thousand kilometres, or a couple of hundred thousand miles. It will surely have wear. If the kilometres are under 100 thousand or under 60 thousand miles and the vehicle has been well serviced; never run out of oil, then it would be very strange for it to have an oil burning issue. If your vehicle has done a lot of work and is showing other signs mentioned then it may be at the end of its life.  It is important to note that you only have to let the engine oil run low once to cause catastrophic damage to the motor.  This hardly seems fair.  But it is the case.

 What will a mechanic do to test and confirm my concerns?

  • A mechanic has a device that can test the compression of a motor or engine. Basically the compression tester goes in one of the spark plug holes and as the motor is cranked by the starter motor it will show the pressure build up in the cylinders. A loss of compression from the standards laid down by the manufacturer for the motor in your vehicle, will tell the mechanic how badly worn things are. This is usually pretty accurate as far as a test of the engine wear goes.

To sum up, let’s say that our engine is blowing blue smoke under acceleration, it does seem sluggish up hills and seems to be getting hot too. When the oil filler cap is removed there are visible fumes blowing out with some pressure. Ok, so now with this set of questions answered we can pretty safely say, we have an oil burning engine on our hands.

Why does the engine or motor smoke?

The engine relies on very precise tolerances between operating parts. It needs oil between all these moving parts too. This avoids the motor seizing or locking up due to friction. But you can imagine that if over time, due to wear, the gaps between these parts gets a bit too wide we can get an issue where oil ends up where it should not be in large quantity. Such as in the combustion chamber. You can imagine that if we put oil on a fire we are going to get smoke! So what happens is the oil in a worn motor is allowed to pass by things like valves and piston rings. This allows it to get into the combustion chamber and with each firing of the fuel air mix the excess oil gets turned to smoke. The harder you work the motor the worse this gets. It can often be called bypass. Not only does the oil bypass the seals, but also the pressurised gas. This also means that the pressure can flow back into the crank case and up into the rocker covers. If you did the check of removing the oil filler cap. Then you may have seen those fumes. The ones that bypass the sealing engine parts such as the valves and pistons.

The two illustrations below show in very simple graphic terms where the oil and pressure bypass the worn parts.

Oil Bypasses Worn Rings And Valve Stem Seals

Oil In The Engine By-Passes Seals And Piston Rings
Oil In The Engine By-Passes Seals And Piston Rings

Hot Gasses Bypass Worn Valve Stem Seals And Rings

Hot gasses bypassing worn rings and valve stem seals
Hot Gasses Bypassing Worn Rings And Valve Stem Seals

 

What can I do about this problem?

It is possible through diagnosis to find that the valve stems are worn according to the graphic but the piston rings seem ok.  Or vice versa. Some mechanics may advise getting the head reconditioned as a cost effective option. This can be a very short term fix. What can happen is that the reconditioned head which now has the full seal back pushes the pressure right up to where it should be. But due to the bottom end and rings not being put back to standards, the extra pressure now starts to bypass the old rings. Even if it was not doing that before. This is due to the old rings not really bypassing that much under the low pressure of the worn and tired valves keeping the pressure extra low. So often what happens if one part of the motor is re-built is that the other will fail due to the extra pressures being placed on it by the reconditioned parts. The best options are to either recondition all parts of the motor. Or alternatively get a replacement used engine that has plenty of miles/kilometres left on the clock.  Here is a great place to buy used engines with plenty of miles left on the clock.

Anything short of these two solutions will usually come back as another problem in the near future. Please also see the section on fitting a replacement engine for other useful tips about the cooling system etc.

Having tried many short cuts over the years, I can vouch for how much money I have wasted not doing the job correctly from the start. If the motor is showing that it is an oil burner then it is really a terminal engine and is needing to be replaced or given an extensive reconditioning.

Why not just keep driving?

Well often you can for a while. But remember the EPA (Environmental Protection Authority) or RTA (Road Traffic Authority) may think otherwise. In many states, it is encouraged to report offenders. So it is probably only a matter of time before you get caught and end up with a fine.

Beside the penalty for being a polluter there is also the issue of pollution to the environment at a real and moral level. The more people that make sure they have an engine in good working condition in their vehicles, the less pollution we have. This will help us all minimise damage to our shared air quality and cut the detrimental effects to human health. So consider all these things when you are working out what to do with your old smokey.

If you put a replacement power plant in, you will often feel the joy of driving a fully powered vehicle again. Often we don’t realise how much power the old work horse has lost. With a freshly replaced well performing engine, driving can become a joy again. Not to mention avoiding having to stop constantly and check that fast diminishing oil level!

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71 thoughts on “My Engine Is Blowing Smoke! What Does It Mean?”

  1. Hi Chris, Glad you liked the post. I am hoping that this information helps someone that may have run into this sort of problem and be wondered what to do or how bad it is. There will be more posts in this diagnostic series too! Regards, Lance

  2. Blown away:)
    Great information for everyone, very useful. May prompt anyone to go out and lift there bonnet to check as we speak, also think anyone buying a car could also use this information as a guide. Cheers Greg,

  3. I’m really loving the theme/design of your blog. Do you ever run into any internet browser compatibility issues? A small number of my blog audience have complained about my blog not operating correctly in Explorer but looks great in Chrome. Do you have any ideas to help fix this issue?

  4. Hi There,

    Thanks for the kind words. I checked out your site on chrome and IE10 and all looks good to me. In fact it looks cool! Nice gear 😉 If you can get more specific feedback that could help problem solve. Often what we assume is an issue is not the case. If you can find out exactly what people are having problems with then its something that can possibly be fixed. We have a great dev team, so they may be able to comment if you get details. Kind Regards, Lance

  5. I have a whole case of Kendall Motor oil glass jars plus the box they came in. All of them have there labels and the case is in good shape. Any idea what it might be worth?

  6. Hi Sayed, Some of these older motor oil bottles in good condition can be worth quite a bit of money! Send some pictures if you like and maybe someone will come in with an offer or idea of price. links@autoadvantagesales.com Kind Regards, Lance

  7. Thanks for sharing this article. It has explained me well about the different colors of smoke that is coming out of car and its cause. I have gained a lot of information from the pictorial description too.

  8. Hi Rogers, Glad you got some benefit from the post. I see you offer some great warranties on your engines too! Nice one. Regards, Lance

  9. my car is blowing blue smoke when start and using oil when alot brought from wrecking yard

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  10. My car starts blowing grey smoke out the exaust pipe if I leave it running without actually driving for too long. It gets more smokey the longer I sit. but returns to normal after a few minutes of driving. I need to replace my EGR valve. Could this be the cause of the smoke?

  11. I was in cruise control on the interstate and going up hill my car dropped to 3rd and heavily accelerated. After about 5-10 seconds I noticed white smoke out my back windshield. It didn’t last long and has not shown up again, but now my car seems to have lower power up hills and has trouble shifting out of second. Any advice as to how concerning or expensive this problem is?

  12. Hi i have a 97 rs legacy and its blowing a lot of smoke and oil on to the top of my engine also is poping the dipstick out any thoughts on what the problem could be

  13. Car just starting doing blowing smoke last time I filled up my tank, I normally run ULP91 but tried 95 premium I’ve noticed a white / blue smoke but only once putting the foot down if I’m driving along I don’t seem to notice it but when accelerating out of a corner or up hill or on the highway but it’s not the whole time just occasionally. I’m thinking running to rich change plugs fuel oil and or add Nulon stop smoke and or fuel

  14. Great information. My car is blowing off black smoke only under high acceleration. I checked the oil cap test and yes there was a little of some coming out under median pressur. Also I found that the oil is getting low and that it does not go to the ground so it goes somewhere else on the engine. I came to believe that the smoke is occurring is due to the oil leeks once engin gets hot under high acceelation. Good news is the temperature reading in my car is average and does not go above the middle mark. thank you again for the good information, I believe you are a great mechanic.

  15. My 1999 grand am gt 3400 has been smoking white smoke. After just a few minutes it stops. My car does have a pretty bad miss to it when I first start it but does smooth out after idling for a few seconds. It does have lots a miles like 218,000 . Has excellent power. It doesn’t use oil. Engine isn’t loud. This last time I changed oil I used the oil made from natural gas. Do you think that this could have anything to do with the smoking because it is due for a change. We did replaced the intake gasket about a year ago. It isn’t running any hotter. Any help would be greatly appreciated. Thank you in advance

  16. I have a 98 mitsubishi eclipse 420a 2.0L Non tturbo. It smokes out of the exhaust but not consistently I know it’s burning oil but it’s not all the time. Any suggestions?

  17. Tiny question. I noticed my car loses power when I open up the oil cap and even seen some fumes leaving. However I haven’t seen any smoke coming out of the exhaust yet. The thing is I need to drive 500 miles this Friday. I’m planning to have the oil and spark plugs changed before the trip (tomorrow). With your experience would you say it will hold it and fulfill the journey? Or would you suggest me to abort the mission.

  18. Thanks for this… Its helpful and easy to follow and plus im a 17 year old girl who knows absolutely nothing about cars so i really needed a specific explanation of things thanks again☺️

  19. Good article ! I have a 253 co v8 motor which is blowing smoke after rebuilding it ! I have compression tested it and I have a consistent reading of 150 psi on 7 of the eight cylinders and 120 psi on the eighth ! Could the smoke be from a broken oil ring after the rebuild or some other cause ?

  20. Hi there Lance.

    I have a very strange problem on my hands and running out of ideas.

    I have an 2009 Audi 1.8T Sportsback 6 speed with 180 000km on the clock.
    The turbo has been ‘refurbished’.
    The car is serviced on a regular interval. Never used oil in the past. I had the PCV valve replaced with a genuine part and all the compression tests and everything has been checked. There is no sign of burnt oil anywhere. However. After 500km. The oil light comes on asking for oil. I then top it up with about 2.5lt of oil.

    When I accelerate hard, just rev up standing still, there is a black ball of smoke out the rear end of the exhaust .

    Can this mean that the rings are done and needs replacing?
    What other tests can one do to confirm what is going on with the motor?

    Thanks for your info on this article. Very helpful information.

  21. hi,I have a Toyota ae110 and the problem that I have is that when it has idle for some time then I push the acceleration pedal in it smokes once then after taking off its back to normal and it doesn’t smoke even for a long distance but only when it idle

  22. Hi,

    I bought and overhauled an engine on a Opel Corsa 1600, and the valve guides was replaced, and the valve seats machined deeper by an engineering company.
    After I assembled the motor we took the car for a ride for about 150km, and the next moment we noticed smoke starting to get worse and worse as we were on our way home, and the next moment the oil light started to go on and of until it remained on.
    I stopped and asked one of my friends to assist with 2 liters of oil in order to get home.
    I removed the plugs and carried out a compression test which read:piston 1 = 12bar piston 2 = 12.5 bar piston 3 12bar and piston 4 = 6 bar, and piston 4 plug is soaked with oil, which caused me to drag along home on 3 cylinders and now and then the 4th cylinder kicked in some more horses.
    At home I removed the head and replaced the cylinder head gasket, boxed up and carried out a pressure test, which indicated that all 4 pistons was in the range of 11.5 each….
    I started the car and after 1 minute the smoke was back and worse than ever.
    What can this be?!
    I mean it looks like the oil pump is pumping oil directly into my combustion chamber.
    I left the vehicle in my garage as is and never touched it again for the last 5 days, in order to calm down and seek for advice.
    It the engineering company damaged the head in such a way that the oil enters the comb. chamber, then how can I gain 11.5 bar after the gasket was replaced.
    I do not know if anyone can give me some advice on this, for I have already spent a lot of money on this engine, and I really need to find a cure before replacing it

  23. Hi I’m looking to buy a car but on the ad the guy says the acceleration smokes but he didn’t say what color but he did say he has to put oil in the car every 600 miles.. so is that a bad sign? Should I still get the car?

  24. Hi, thanks a lot for the very useful tips. My car broke down last night on my way to a meeting, i wenf over a speedram relised engine had gone of parked pushed the gear on park and turned the engine on, it would start but soon run off again, tried several times till i noticed heavy blue smoke from the mirrors and atmosphere, later it wouldn’t even start, i know and noticed my oil was low, since about a month ago i changed my crankshaft seal which made the car loose a lot of oil,my general maintenance and oil change will be due in 10th of march which was why i was waiting till then to change the oil. But now i realise i have to fill up the oil and it will work perfectly!

  25. I’ve noticed the blue-white smoke spewing from the back of my Jeep when on the highway but it only gets bad upon release of the accelerator (coasting) not on accellerating.

  26. Hey lance! Awesome post. I feel like one of the possible issues you talked about might pertain to my old honda accord haha I noticed my engine started smoking a bit after i treated it with degreaser. After reading your blog i’m not too sure if it’s just a coincidence that after I degreased maybe the engine was finally tapping out from how long it’s been running, or if the degreaser actually messed something up under the hood. I’ve also already have had an oil leak for maybe 2 years now and I’ve constantly had to fill the engine with oil maybe once every week in a half. My father thinks it has something to do with the gaskets. But i’m young and learning so I have no idea what alot of these things are. Point being though is my engine smokes up a little now when The car is on. It seems to gradually get more smokey as the car runs. Never had this problem until i degreased under the hood. Any pointers?
    Respectfully, Bryson

  27. Hie
    Thank you for a great article.My mechanic changed the head gasket on my BMW 5.23i but did not change the seals as well. On my way home from the garage, i noticed smoke belowing which wasn’t there before. I pointed out to him and he went on about my female driving over revving thing which he insist caused damage the damage to my seals. after reading your article it made sense so i am going to give a good lecture and am not going to pay him coz he was ripping me off. In future, before i take my car for repairs or service, i will check out your website for advice or else the guys will always take advantage that i am a female.

  28. Hi my name is Bendu, I just want know the problem with my car today at about 2:45 pm I was trying to start my car when put in the key I turned on and than turned off car right away after that I saw smoke small amount of smoke coming from the engine and under the car and sound of the engine changed to heavy nose so I really don’t . so please can you tell me what might be the cause.

  29. Hello. I have a 2012 Suzuki SX4, recently I waited too long to get the oil changed, and when I did take it in to get an oil change, the mechanic stated he could not help me. He said there was too much black gunk in the oil and that I needed to get the engine “flushed”. I had the engine flushed and was told it “wasn’t as bad” as I was led to believe. Appoximately 2 weeks after the flush,my car exhaust has white smoke coming out the exhaust. Just a little when starting, but alot when accelerating. The smoke stops after driving car for just a few minutes. We recently had a bad storm where I live and it’s possible excess water got in my engine. But would that cause it to smoke so bad? Now that the car has had time to dry out, is it something I should be concerned about? My instincts tell me something’s not right..but my gauges are fine and no excess gas use when it runs. I recently drove over and hour and no signs of smoke. I came home and parked the car. When I went to go to the store, about 4 hours later, the car once again billowed smoke as I accelerated out of the driveway..then stopped smoking. This has only happened twice…But it is a lot of white smoke ! Could this have anything to do with the recent engine flush and oil situation?Or the flooding situation we had? My car did not get submerged, but it’s possible it got very wet, we had over 12 inches of rain. Please reply and thank you.

  30. Cars are not in my expertise, but I do know that smoke coming out of the engine isn’t a good sign. The smoke is slightly blue, which according to you is oil burning. Does that mean I put in the wrong oil, or am I low on oil? Maybe I should get it taken to the auto shop for an inspection. Any other ideas?

  31. My Mazda 6 2.2 2010 has just had 4 new injectors due to blowing smoke and a knocking noise , the knocking noise has stopped and the smoke levels have reduced slightly , but now it seems that it’s blowing blueish smoke periodically , only after a long run ??? Please help ?

  32. I HAVE A NISSAN ARMADA 06, WHEN I START THE TRUCK IT PRODUCES SMOKE AT THE BACK WHICH I CAN EASILY SEE THROUGH THE SIDE MIRROR. NO SMOKE WHEN DRIVING. I TOOK IT TO THE MECHANIC THEY SAID I NEED TO DO A MAJOR TUNEUP WHICH I DID STILL SMOKE COMES OUT.
    I WENT BACK THEY SAID I NEED TO WORK ON THE VALVE WHICH I DID BUT STILL SMOKING PLS ADVISE ME.

  33. my care burn good at all valves plugs not oil spilled when driven uphill minimal blue smoke is given off on straight no smoke what can be the cause
    tx desmond

  34. help please lol 4 clinder chevy malibu
    ok so my car needed a new radiator was over heating and leaking and was replaced and now it still overheats but not when the heat is blowing..i did not watch it get replaced so I cant speak if it was installed correctly mayb? i thought maybe something was wrong with my oil light or just needed a oil change so i didn’t add oil beause i have..so i didn’t notice how much i was driving and i drove some distance and my car preety much went putt putt a couple of times i let it cool and made it to get oil which i believe it needed at that time my oil light was going off but i did see my engine light blink when it went putt putt so i added and drove it later when i got on the freeway after somtime i seen a big cloud of white smoke come out my tail pipe and a small amount come from my engine but it stopped i was thinking (hoping) it was from the lack of oil .
    but now its fine seems to have less power kind of..and it will over heat if i don’t put the heater on please help it still does smoke when i start it up and drive for a small amount of time what does all this mean??? i have no check engine light on somebody feel free to reply thru my email ..is my car going to blow up or catch on fire or ..?

  35. my car show black smoke,when I accelerate on idling, but the oil was due to change which I fail to do,and also short oil due to small leak at the sump cover toward crank shaft

    , pls what should I do

  36. I have Toyota 4runner 2002 model, under heavy acceleration, passage of soot surfaces. Runs down my petrol very fast. Leaving my pipe end with black stain. Mileage is 67000miles. Please I need help.

  37. Hi guys. Please help. I have a BMW 318I, 2004 model. I did a service on the car, changed the gasket cover and the VVT motor.Unfortunately the mechanic didn’t it properly so it was leaking oil and it started smoking. I went back to him, he tightened the system and looks so far that the leak has gone but not the smoke. The car smokes when for instance am about to take off at robots or stop signs. What could be the problem please help am very worried.

    Emmanuel.

  38. ok I have a 88 supra. Tons of smoke 5 min after fire up. Has new head gasket head decked block decked with proper hg. It smokes ALOT when you rev it. It dissipates a bit slower than coolant, but doesn’t seem to last as long as oil would. However in 40 degree F weather it will smoke screen the car behind it. compression and leak down test pass. o2 sensor colored light brown. no oily residue or watery residue. the motor is a 7mge Toyota. I checked the radiator for bubbles there are none. Motor builds pressure properly, oil has stayed clean so has coolant. There is no excessive pressure build on the coolant system (but it smokes so bad I cant drive it to the highway and warm it all the way up.) In fact there seems to be a tiny rythmic suction on the coolant system when you cold start it and seal the top of the radiator cap with your palm. Could a internal head crack cause this? EGR?, the tiny water port on the very bottom of the intake? (plugs all looked the same a bit sooty), a mix of 3 yr old and new gas with some lucas fuel treatment is in the tank,(it doesn’t smoke right at fire up) what if a couple valve seals tore or didn’t seat right and popped off and are letting a lot of very clean oil into the motor could that cause grey brown white smoke. I have shined light on it of different shades the smoke is a brownish grey white. what about a stuck fuel injector? (spark plugs weren’t wet though)

  39. Gasket cylinder bloated, I took to the dealer,the car repaired,they call me to pick the car is finnished, it was just seconds I left the place,car showed oil sign I went back to the dealer,they fix the problem, second day I saw smoke from exhaust and bonnet grey and white smoke and car lose power I bring back to the dealer, they told me that car had another problem. Not same problem which I don’t understand,and they asked if I put another oil in the car, I said no I was not supposed nw they don’t want to fix the car they say I must take it pls help

  40. My problem is the same as you Emmett Whisenhunt, my car is a E36 with M52B25 engine. The engine has a new gaskets seals on it. And already had cleaned all the head and valves, from the previous compression test resulting in 12:1 comppresion ratio for all cylinders (which is good).
    Also checked on all of the spark plugs and all dry, not oily or wet. However when I go uphill with slight accelerator (2K rpm) my car starts to smoke a quite much (because I can see from my rear view mirror).
    If anyone have explanation and the steps I should do with this condition..

  41. SPECTACULAR!..IT REALLY HELPS ME A LOT OF MY CAR..THANKS LANCE…REGARDS TROY VALLEJOS FROM PHILIPPINES

  42. Hi there I got a Seat Alhambra 2.0 litre TDI and it is releasing blue and white smoke, the acceleration is restricted and only smokes when the cars at normal temperature but it is not the turbo as my mechanic has looked at the turbo and it’s fine. It is not burning a lot of oil but when I rev it I smell oil burning. The pipe that send oil to the turbo was insecure but we had tightened it. please can I have a reponse

  43. I drive a 2006 Model Altis. It emits white smoke after being caught in a traffic or after taking queue on a fast food drive. The engine temperature is low. I also noted that the engine oil is decreasing evry time it emits smoke.

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