6 Causes of a Car Blowing White Smoke From the Exhaust

If you see white smoke coming out of your vehicle’s tailpipe, then you should understand the various root causes to avoid any potential engine damage. One of two conditions is responsible for white smoke blowing out of your exhaust.

In most cases, especially in the winter, some white smoke from your exhaust is perfectly normal and not something to worry about. But other causes may be cause for alarm. Keep reading to help understand why this happens and when you need to worry about fixing the issue.

Top 7 Reasons White Smoke is Coming From Your Tailpipe

If you are in the unfortunate situation where white smoke continues to come out of your exhaust after you’ve let your car warm up for more than a couple of minutes, then you could have some internal problems taking place.

It’s important that you address the issue soon so that your engine and exhaust system do not get damaged in any way. Here are 7 of the most common causes of a car blowing white smoke from the exhaust pipe.

1) Condensation Burn Off

white smoke condensation

If you notice white smoke coming from your muffler, don’t automatically assume the worst. You may not have to worry because it could just be the accumulation of condensation causing that to happen.

In these situations, you will typically see this white smoke come out on cooler days. The smoke should only be coming out in small amounts after you start your engine. Then after about 30 seconds to a minute, the white smoke should clear up. If this is the case then you have nothing to worry about.

2) Cracked Cylinder Head

Whenever your cylinder head is cracked or damaged, coolant will begin to leak out of it. This doesn’t need to be a big crack either. All it takes is a little bit of coolant to leak out and get mixed in with the engine oil.

Once that happens, the oil will become contaminated. The first sign of having contaminated oil is white exhaust smoke coming out of the tailpipe. As this continues, the white smoke will begin to have a sweet odor smell that won’t go away.

3) Damaged Coolant Reservoir Tank

coolant leak

Another area that can leak coolant is the coolant reservoir tank. This is generally less common to leak, but it can happen if the reservoir tank were to get damaged or cracked.

Sometimes this will happen if it a mechanic is fixing another problem in the vehicle and accidentally damages the tank. In any case, you’ll need to replace the reservoir tank whenever it is damaged.

4) Oil Leak

damaged piston

If oil were to ever leak out of your piston rings or valve seals, then it would flow into the internal combustion chamber along with the fuel. Once the fuel and oil get mixed together, it will cause to come out of the tailpipe. The color of the smoke will actually be blue-ish but it will appear to be white smoke to some people.

You would obviously want to fix this leak quickly because if the engine components are not being lubricated properly by the oil, then they’ll start to get worn out and damaged rather quickly. This will cause a whole other flock of expensive problems that you won’t want to have.

5) Bad Fuel Injector

fuel injectors

The fuel injector is responsible for injecting fuel into the internal combustion chamber at the exact right time. If you were to have a bad fuel injector, then it would cause white smoke to form because the proper amount of fuel did not enter the chamber at the right time.

6) Engine Control Unit Error

bad ecu

If you have a faulty engine control unit or one that simply is glitchy, it may throw off the timing of the fuel injector. This doesn’t mean the fuel injector is bad or anything. It just means you need to fix or reprogram the engine control unit so that it can correct the timing of the fuel pump injector.

Often, you can simply unplug your car battery for a few minutes to reset the computer and the issue fixes itself. But if not, you would need to go to your dealership to get this done because it requires expert mechanics who are familiar with your vehicle’s engine to reprogram the engine control unit.

7) Cracked Engine Block

cracked engine block

The worst case scenario is that your entire engine block has a crack in it. These are the kinds of problems that will be the most costly to fix. You probably aren’t going to know which of these problems is causing the white smoke to get produced until you have a mechanic look over your vehicle and perform a diagnosis on it.

Conclusion

So basically, the only time you don’t have to worry about the white smoke is when it clears up within a minute or so of starting your engine. If the white smoke stays on longer than that, then you need to determine which of the other six causes above are the problem and hire a professional to fix it.

18 thoughts on “6 Causes of a Car Blowing White Smoke From the Exhaust”

  1. I had my radiator cap blow off while driving the engine got so hot. I installed a new thermostat and flushed the radiator as well. My tailpipe produces white smoke now. Is this a bad sign for my motor?

    Reply
  2. I have a 2016 Toyota avensis diesel 1.6 the car was driving fine dpf full engine service needed came up on the dash stayed on for 2 days went off now the car is leaving out white smoke form the exhaust while accelerating and idling no smoking until car gets hot what would you think the problem is

    Reply
    • You may need to do dpf regeneration with a scan tool beacause soot content may have clogged your exhaust.if you don’t do it quickly, it may mess up your engine

      Reply
  3. My car shuts off while driving an steering wheel an breaks kinda lock up an white smoke comes out of my exhaust

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  4. My car has shot a cloud of white smoke twice serveral months apart. Both while accelerating. Both while around 3000 rpm’s. Thoughts?

    Reply
  5. My car had a big white cloud coming from it’s exhaust a few weeks ago when I was driving up a large hill. A firefighter escorted me to my home city ~ 30 miles away (The smoke stopped after a couple miles past the hill). I have not noticed any more smoke since, although I also haven’t climbed a hill as big as that.

    I intend to use a combustion leak test kit, but I’m wondering – is it Is it possible to have the smoke happen only once, and not be indicitive of a greater issues (such as broken head gasket)?

    Reply
  6. I have a Mercedes Benz Viano 3.0 v6. When I put diesel in and the needle is above quarter its smokes. I will take it for a drive about 20 km and when I get back the smoking has stopped. It will be gone for about a month to 2 months and then start smoking again. when the fuel is between reserve and quarter it will stop smoking. the smoke has a bad smell to it as well. Can this be a result of faulty injectors .

    Reply
  7. I have 2015 Ford Focus…First sign of problem the Ac stopped..result of fan not working… Within same drive car got really hot and Warning light message to stop engine immediately showed on dash. I pulled into parts store.. added oil..coolant and drove. Within 5 miles engine stayed cool but now thick white smoke from exhaust. I did spill oil into spark plug reservois. I changed plugs wiped out oil..but car still smoking. Any suggestions????

    Reply
  8. HI
    BMW 320i touring 2006. I have random white puffs of smoke from exhaust. Driving along happens at approx 15min intervals. I have had a oil leak for ages 2 rocker gaskets, 2 vacuum pumps, o rings now rocker gasket and rocker cover about a week ago, seems to have cured leek but the puffs of smoke started a couple months ago. Thought the oil leek was the cause. Any ideas.Thank you

    Reply
  9. My 2015 Nissan Pathfinder started to have a cloud of white smoke come from the exhaust on startup, but went away in a few seconds. I parked the car for a few weeks, and checked all fluids, checked for any leaks, and ran Seafoam through the gas tank. I checked my plugs and all look great. Stopped smoking at startup so I drove the car to work. Now the smoke is continously coming out. It doesn’t smell like oil burning or sweet like antifreeze. The smoke is really thick. Any ideas?

    Reply

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