your car is blowing blue smoke, it’s a clear sign that the engine is burning oil. What happens is that the valve guide seals or piston rings are worn out, and oil is leaking past from where it should be lubricating the moving parts, to the combustion chamber where it’s being burned up with the fuel.
If you’re seeing this kind of smoke, check your oil regularly and watch for consumption issues. While an issue that normally should require immediate attention and expensive repairs, including some internal replacement parts, if your vehicle is old and the leak is minimal, it can be carefully managed by topping up the oil on a regular basis.
Along with environmental damage, burning oil can cause rough starts, as the process can ruin the car’s spark plugs.
There is another reason for blue smoke, and that’s if the car is turbocharged; the smoke being a sign that the blower is in need of rebuilding or replacement.