Hello, I have a Mini Cooper 1.6 120 horsepower, 2006. the low oil pressure light comes on. We have 4 bars on a cold engine, 0.5 bars on a warm engine. The dragon, oil pan, oil change and installation of the original filter were not cleaned. What should be the correct idle pressure when the engine is warm? I am asking for professional advice. I have a choice to sell a car or repair the engine ..