Normally, your car’s exhaust should barely be noticeable, quietly pumping out gasses from the combustion process from the back of your vehicle. But in case of a problem, then white, black or blue smoke could start appearing from the exhaust pipe. This annoying exhaust smoke could be coming out of your exhaust pipe when the car is either stationary or running, and it may cause an immediate sense of dread that an expensive repair bill is on the way. Below is a list of different exhaust smoke colour and causes
1) Blue smoke: Blue smoke from exhaust is most times accompanied by burning smell. It means that there is oil entering the system somewhere. Engine oil is meant to lubricate moving parts, and not expected to enter the fuel system if a car is running properly.
2) White smoke: This could be steam as a result of condensation in the exhaust pipe or a more severe issue caused by a leak in the engine coolant. Large amounts of white smoke could mean head gasket failure.
3) Black smoke: Like the other types of exhaust smokes, there are also different causes of black smoke, and one of the main factors to take into account is whether your car is petrol or diesel-powered. In a petrol vehicle, black smoke means that too much fuel is being burnt while in diesel cars, it could be soot build-up from unburnt diesel. The diesel particulate filter (DPF) is designed to trap soot from unburnt diesel before it pumps out of the car’s exhaust, but if you only ever drive a diesel car at low speeds, the soot deposits can build up over time, and could result in a warning light flashing on the dashboard.
4) Grey smoke: Just like blue smoke, grey smoke could be a sign of excess oil burning somewhere in the engine, but there are also other causes such as a faulty PCV valve (Positive Crankcase Ventilation) which is one of the most basic forms of emissions control, drawing unburnt fuel back from the lower part of the engine to the upper part.
In case of a car with an automatic gearbox, then a reason for grey smoke might be that transmission fluid is being drawn into the engine through a leak in the system. Again, this could be a costly repair and will definitely need more attention.
DISCLAIMER AND RECOMMENDATION
These issues have to be looked at and repaired by an experienced ASE certified auto repair shop and not do the repairs yourself.
Nadia, the owner of Mobile Auto Diagnostics and Repair LLC has 18 years of hands on experience in repairing all kind of vehicles. She has 11 ASE certifications, one of which is an ASE Master Mechanic certification.
Nadia’s auto repair business is by invitation only and is not open to the public. Please contact Nadia by phone or e- mail found on this website.
Nadia accepts cash, checks and/or major credit cards.
