Starting engine without oil
Because our cars have an oil level sensor, i wonder if it is possible to start a N52 engine without oil? Is there a kind of low level switch limit to protect the engine?
I suspect my car was started without oil at the dealership during my last oil change. I let the car in and took a walk to the Ford dealer to buy some parts for my other car and when i came back, the oil change was done and the young tech seemed nervous when i went in the garage to talk to him about the work and the inspection he performed at the same time. (Usually i stay next to the tech when my cars are serviced but not this time..)
When i left with my car, i noticed the RPM was shaking a bit, but then was ok and i went to a drive thru for lunch, and i could hear a kind of grinding noise reverberating to the wall with the window down. The noise was not there before. I got back to the dealer and they said everything is ok and could not really hear the noise. The noise is subtile but is there and was not there before the service. Oil level is ok. The noise is present from 1200 to 1800 rpm and passed this speed, it seems to fade away with the other noises. To me it seems like a valve train noise, and is present during acceleration and deceleration of the engine with load or not..
I'm thinking of taking vibration measures of my engine and go back to the dealer to measure one of their cars to compare..
What do you guys think?
Current fleet :
2011 E90 N52B25