My 2006 750li the Engine light and really all the lights come on

What is your question?

Then the lights goes off except the engine light I had the oil change very expensive oil the car has 100 thousand miles the car runs good but I went and had it diagnostic it said code 3 he said I need to get new valves covers the valve is plug they are 500 dollars apiece he said I should just another engine put in it would be cheaper the car is a beautiful car no dents inside is beautiful what advice you can me