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My Engine Blows Blue Smoke – Black Smoke – White Smoke
Free Smoke Test
We do get asked a lot about what does this colour smoke means.
So we put together our smoke analyses
Why does my Diesel engine blow black smoke?
Black Smoke indicates poor and incomplete combustion of the diesel fuel.
- – Block air filter or intake system
- – Problem with fuel injector pump or injectors
- – Engine timing out
- – Low cylinder compression (i.e. cylinders, piston rings, ring grooves)
- – Restricted induction system
- – Excessive carbon build-up in combustion and exhaust spaces
- – Incorrect valve clearance
Why does my diesel engine blow blue smoke?
Blue Smoke is an indication of oil being burnt.
- – Low cylinder compression (IE cylinders, piston rings, ring grooves)
- – Worn oil rings – sticky oil rings when cold
- – Worn valve guides or seals
- – Cylinder head pooling oil, valve oil drains blocked /sludge and poor PVC valve, similar to valve stem seal problem – called the “sludging” issue. A common issue on later model engines past 2003
- – Cylinder glazed
- – An incorrect grade of oil (eg oil too thin, and migrating past the rings)
- – Fuel dilution in the oil (oil thinned out with diesel)
- – High engine oil level
Why does my diesel engine blow white smoke?
White Smoke occurs when raw diesel comes through the exhaust completely intact and unburned.
- – Faulty glow plugs
- – Low engine cranking speed
- – Problem with fuel injector pump or injectors
- – Incorrect injection timing (could be a worn timing gear or damaged crankshaft keyway)
- – Fuel air leak
- – Low cylinder compression (ie cylinders, piston rings, ring grooves)
- – Incorrect valve clearance
