A smoky exhaust isn’t always a reason for concern.
For instance, if the smoke being emitted is vapour-like, you don’t have to worry.
Vapour-like exhaust, which disappears almost immediately, is probably just water vapour.
This is normal and sometimes occurs after a car has been parked overnight.
It may just be due to condensation in the system.
Condensations occurs when there is enough of a temperature difference, such as the weather suddenly cooling overnight.
However, there are other instances that should be a cause for worry.
Smoky exhaust can be caused by a dirty air filter.
A dirty air filter can cause the emission of black smoke.
Not enough clean air is getting into the engine, so after combustion, the exhaust turns smoky.
However, if the black smoke is scarily thick, the problem may be much worse.
It could be a cracked engine block or cylinder head. The latter may cause more fuel to leak into the cylinder.
When more fuel than needed is burnt, black smoke may be the result.
Head to your workshop immediately!
Burning oil causes blue smoky exhaust.
When engine oil leaks into the combustion chambers (cylinders) and gets burned along with the fuel, blue smoke is emitted.
This is the reason why you see some motorcycles emitting blue smoke.
These bikes are usually two-stroke machines, which naturally burn a bit of oil.
However, cars have four-stroke engines that do not need to burn oil.
If you see your car emitting blue smoky exhaust, send it to your workshop at once!
Thick white smoke is a big problem, too.
Thin white smoke may just be water vapour, but thick white smoky exhaust is a bad sign.
It could mean coolant is leaking into the combustion chamber.
It could also be a cracked turbocharger.
If thick white smoke is accompanied by some blue smoke and a loss of power, your PCV (positive crankcase ventilation) valve may be faulty.
As with the above issues, head to the workshop immediately.