used car engine exhaust and oil smell of engine

Not sure sure what exactly all that your asking? Do not have pictures of different colors of smoke from the exhaust pipe. Blue smoke is just that it is blue and would be heavy and would not quickly disappear.That is oil burning and a lot of it. Black smoke would be excessive fuel burning out the tail pipe. White smoke would be coolant burning out the tail pipe.

Smoke colors are sort of subjective but in general.

White smoke from coolant burning looks like this -
https://www.youtube.com/watch?v=l3t-MQS-PYk

Blue smoke from oil burning as it drifts you can see the bluish tint to the smoke. This smoke will stink, it does not come close to smelling good. -
https://www.youtube.com/watch?v=KICpEmJ8OKo

Black smoke - Hard to see it but it will be dark colored smoke, usually thin, sometimes you can small the excess fuel.
https://www.youtube.com/watch?v=wmXuEs0OKJI


Engine oil -
Black oil - has not been changed or engine is sludged up inside.

Coolant in the oil, will smell sweet, look like a chocolate milkshake and be sticky. (see picture) If the vehicle has been sitting long enough the coolant may settle out. This is even worse as coolant does not lubricate and will destroy the bearings in a short time.

Gas/petrol in the oil - The oil will be very thin and smell of fuel, usually it will be dirty as well as the fuel has "cleaned" the deposits from the engine.