Thank you Everyone!!!!!! I took off the panel and the clue The clue “white” was really because I was started to look after the “white clip”. I changed the filter (it is not easy, since not too comfortable kneeling next to the car on the cement, - being old too) at the first time (the old filter was very clean) even though the car is a 2000 model, - It has only 6000 miles garaged and covered, never saw rain nor much sun (living in Southern California). All service done by me, 14 times changed the oil (Mobil 1 Synthetic 15W-50) and annually the coolant (Mercedes original). I bought this car as a “spare”. Again: Thank you everyone!!!