What causes smoke to come from the engine?

There are several different things that can cause your engine to produce smoke while you are driving. However, it generally means that something is burning that shouldn’t be. If you notice smoke coming from your engine and exiting through the bonnet, it is generally best to pull over and avoid driving until the problem can be properly diagnosed. 

Below is a list of common causes that may help you to diagnose why smoke is coming from your engine:

  • Coolant leak – When coolant is leaking, it will enter your engine cylinders and be burnt with fuel. As the coolant burns, it will leave your engine as white smoke. Coolant leaks can have many different causes with different levels of severity. The coolant leak can be caused by a damaged hose, radiator or tank, or it can be caused by a blown head gasket.
    Coolant leak fixes in Hamilton >
  • Engine overheating – if the coolant leak is large enough, this can cause your engine to overheat, and produce smoke and steam.
  • Worn Engine – If you notice blue or grey smoke, it means that the car is most likely burning oil. This can indicate that there is a major problem with the engine, and you need to get the car to a mechanic as soon as possible.
    Oil leak fixes in Hamilton >
  • Clogged air filter – The air filter stops contaminants from entering the engine. If it becomes clogged, black smoke may be produced. In order to fix this, a simple air filter replacement will be needed.
  • Car burning too much fuel – A rich air/fuel ratio occurs when your car is burning too much fuel. It causes your car to incorrectly burn fuel, which will leave in the form of black smoke. 
  • Wiring fault – if your car develops a wiring short circuit then the copper inside the wires can heat up and melt the wires insulation causing large amount of toxic smoke
  • Oil leak onto exhaust – if you engine develops an oil leak that allows oil to drip onto your engine’s exhaust pipe, then this can also produce large amounts of toxic smoke, and the oil can possibly catch on fire
  • Blocked exhaust – if you car’s exhaust pipe gets blocked, then this can cause your engines exhaust gaskets to fail, allowing toxic exhaust fumes and smoke to fill the engine bay under the bonnet while driving. These poisonous exhaust gases can also enter the car’s passenger  compartment while you are driving, which is very bad for your health.

What to do if you see smoke coming from your engine:

If you see smoke coming from your engine, it is important to pull over as soon as possible to prevent any further damage from occurring. If the engine is being starved of oil or coolant, it is at risk of overheating being damaged due to a lack of lubrication. 

Getting your car towed may be inconvenient, but it is much cheaper than an engine replacement or your car catching on fire and therefore a replacement car. 

How to assess smoke coming from your car >


Engine Smoke – Diagnostics in Hamilton

Is your car’s engine producing smoke? If so, we can help!

At Grimmer Motors, our skilled mechanics can quickly diagnose the causes of your engine’s smoke problem. Whether it’s a clogged air filter, burnt car wiring or a blown head gasket, we are happy to fix the problem and get your car running correctly again. 

For engine smoke inspections and diagnostics in Hamilton, contact Grimmer Motors today!


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