The importance of an oil cap.
 

Picked up a Rogue from the Tulsa airport and after driving it a bit, noticed a burning smell. It reminded me of the smell of oil had spilled on the manifold when adding oil to the car, so I figured that someone had recently added oil, and that is what happened. Took the wife out for a bit, and when arrived at home, noticed quite a bit of smoke pouring out from under the hood. I popped the hood to see what was going on, and when i did I saw the oil cap sitting by the front, and oil had been sprayed all over the hood and engine. Luckily, I don't live far from the airport, so was able to swap it for another vehicle, and they could clearly see the smoke pouring out from under the hood. Kept an eye on the temp gauge, and did not receive any warnings. Swapped out a Rogue SV for a Terrain SLT, so that was a plus.

Temp gauge is for water. Oil pressure indicator (gauge) is for oil. If you had lost a lot of oil the engine may seize. Engines of today are pressurised for emission control.
At least it did not catch fire.