Engine oil is an absolutely crucial item for any car, regardless if it's diesel or gasoline. There's actually a good explanation why it tends to turn black.

It's standard for older diesel engines to emit black smoke under full load, which occurs during "turbo lag." As the diesel engine waits for the turbo to spool, the machine will blow thicker black ...

"Exhaust smoke ... "White smoke is an indication of unburned diesel fuel. Normally, it would happen at startup in cold weather with lower compression engines and retarded timing.

If you've ever witnessed the thick black smoke coming from a diesel ... and the EGR (Exhaust Gas Recirculation) system. If your diesel engine and its emission system are working correctly, the ...

Black smoke from the exhaust: In a petrol car ... White smoke coming from a diesel engine could be a sign of a faulty head gasket, coolant leak, cracked engine block or cylinder head.

Excessive unburnt diesel fuel can infiltrate the combustion system when your engine fuel injectors ... fuel is expelled through the exhaust as white or black smoke. A good mechanic will be able ...