Diesel Engine Smoke colour serves as a primary tool to understand and get to know the root cause of any ongoing problem with the engine.
Once you fall in love with the sheer power and torque offered by the diesel engines, there is no going back. Diesel engines are not only powerful and full of torque but highly fuel-efficient as well. However, a diesel engine has its own downsides and it is very important to ensure that these engines are maintained really well. A well-maintained diesel engine can go on for years putting up miles on the odometer without any major mechanical work.
One of the most prominent issues faced by the owners of diesel vehicles is smoke. Yes, diesel engines smoke a lot and it’s not just limited to one kind of smoke.
Generally, diesel smoke can be of three colours: black, white and blue. Here is what you should know about the diesel engine smoke colours-
- Black Smoke – Black smoke indicates incomplete combustion of fuel and is a common sight for diesel vehicle owners. A number of issues cause black smoke, such as:
- Dirty or worn out fuel injectors.
- Incorrect fuel injection timing.
- Faulty turbocharger
- Faulty or dirty exhaust gas recycling (EGR) system
- Incorrect valve clearance
- Incorrect fuel to air ratio
- Dirty or restricted air cleaner systems
- Overloading the engine
- Poor fuel quality
- Cool operating temperatures
- High altitude operation
- Excessive carbon build-up in combustion and exhaust spaces
- Blue Smoke – The reason behind blue smoke is engine lubrication oil burning. It is most evident during a cold start. The engine oil can enter the combustion chamber because of:
- Worn valve guides, or seals
- Cylinder &/or piston ring wear
- Cylinder glaze
- Piston ring sticking
- An incorrect grade of oil getting past rings, or valves guides
- Fuel dilution of the oil, making it too thin.
- White Smoke – White smoke is caused by raw and un-burnt fuel passing along with the exhaust gases. It appears at cold start and disappears as the engine warms up. It can be caused due to:
- Incorrect fuel injection timing: If the white smoke is constantly evident, it indicates a mechanical defect or incorrect fuel timings.
- Defective fuel injectors
- Low cylinder compression: May be caused by leaking valves, sticking piston rings, ring wear, cylinder wear or cylinder glaze.
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