Ever found yourself driving in the midst of a haze and realising it has nothing to do with the weather? During your everyday driving, there shouldn’t be any smoke coming from your car’s tailpipe. But where there’s smoke there’s the potential for a breakdown or at least signs of wear and tear in the engine that you may want to bring up at your next car service. Here’s our handy guide to reading your car’s smoke signals: what a smoky exhaust means and when to really get worried.
White Smoke
This is the most common form of exhaust smoke. While it can often be attributed to water vapour caused by a car engine heating up in winter, it may also point to a more serious issue.
If you see your tailpipe leaving a continuous trail of thick, white smoke, this excessive amount of steam could indicate that your car’s coolant is leaking into the engine. This can be caused by a faulty head gasket (the seal between the engine block and the head). This sort of thing should be covered by just about any car service plan insurance, since it pertains to the engine. However, even if your scheduled service is still a while off, it’s best to get this issue seen to sooner if possible. Replacing a head gasket can be pricey, but not half as much as having to repair a cracked engine block or cylinder head.
If left unattended, this leak could lead to engine failure further down the road – an even more exorbitant affair if you don’t have an extended motor warranty. This could mean replacing the engine entirely or just writing off your car completely.
Blue Smoke
Blue smoke from an exhaust is harder to ignore, since it’s often accompanied by a burning smell. More often than not, this is due to oil entering the system somewhere. Oil is only meant to lubricate parts of the engine, not entering into the fuel system, provided everything is working. If you’ve just had your car serviced according to the manufacturer’s motor service plan, there’s a chance that too much oil has been put back into the system. If the smoke stops after a while, then the excess oil has burnt off and there should be no issue. Burning oil can also indicate that you’re using more oil than necessary, so it’s worth checking the dipstick more regularly to monitor any potential oil loss.
However, if this blue smoke persists (and this is often the case in high-mileage cars), it may indicate that certain engine parts have worn away, allowing oil to enter the fuel system around cylinders and valves. Rather play it safe and make sure your car service plan insurance includes valve seals, piston rings, and turbochargers.
Grey Smoke
Grey smoke, like blue smoke, may also be a sign of excess oil burning somewhere in your engine. If you drive a turbocharged car, grey smoke could also be the sign of a malfunctioning turbo. But there are still other causes for grey smoke.
One might be a busted PCV valve. Your Positive Crankcase Ventilation (PCV) valve is among the basic forms of emissions control. In other words, this engine part draws back unburnt fuel from the lower part of the engine to the top, thereby helping to reduce vehicle emissions. While smoke due to PCV failure may look serious, repairing it is a relatively simple job for your mechanic to take care of at your next motor service.
If you drive a car with an automatic gearbox, the cause of the grey smoke may be that transmission fluid is leaking into the engine. Again, this is a breakdown in the making and the repairs to a gearbox can be insanely expensive – that is, if you don’t have an extended motor warranty or have it checked out at your next service.
Black Smoke
As with any of the above, black smoke can have many different causes. One good starting point in deducing the cause of black smoke is whether your car is diesel or petrol-powered. If your car runs on petrol, black smoke is a sign that too much fuel is being burnt. This can be remedied by having your mechanic replace your car’s air filter or check that the fuel injectors aren’t clogged, and that the fuel regulator is clean. This doesn’t have to be an expensive fix, since almost all service plans and motor warranties cover various car filters.
In diesel cars, black smoke can mean there’s a soot build-up from unburnt diesel. This can happen if you only ever drive a diesel car at low speeds. Naturally, the best course of action (which is also the most fun) is to rev up your engine and hit the highway! By doing so, the fuel/air mixture rushes through the car much faster, dislodging the soot in a ball of black smoke.
What Should I Do About It?
Engine damage is unavoidable. While keeping up with your car service plan can help to repair or replace car parts and put off a breakdown, only a motor warranty can cover the unique costs that accompany such an unfortunate incident. So don’t ignore the smoke signs your car is sending you. Hope for the best, but prepare for the worst: get motor warranty quotes today!