It is probably due for an oil change.
Oil is often known as black gold.
its burning oil :(
If its black smoke you are burning oil possibly due to oil getting in your exhaust by tilting the lawnmower on its side or your rings are allowing oil by.
That means that you need to change the oil filter. Or, it could mean that the combustion of the oil is out of tune, and you need to have a qualified oil burner technician look at it.
Oil is called Black oil because it is really valuable and you use it for many things it is for some people really like thy found Gold. So it is called Black Gold
black
Baby oil is not an oil that can be used to whiten black underarms. There are oils you can use in a mixture, such as, olive oil, vitamin E oil, and coconut oil.
It means that you need a valve job. The black liquid is oil from your engine. Your engine is not making a tight enough seal for combustion therefore it sucks in oil and uses it in the combustion cycle. Be sure and check your oil level as im sure that your truck is burnin the hell out of some oil lol
Oil turns black due to carbonation and absorption of dirt. It has to be changed. If the question refers to automatic transmission oil, then carbonation, dirt and worn out clutch plate particles turns oil in to black.
Your oil is probably leaking. If the car is old, then it's likely to be scrap!
Black
oil!