I changed the oil and filter in my '95 C280. The filter that I purchased through the PartsShop came with a large "O" ring seal and a small copper washer. When I removed my old filter, there was a large "O" ring seal but no small washer anywhere to be found. Does this model not use the small copper washer? Or is it missing? I don't have any documentation on this model to help me out. Thanks.