I changed my oil in my 2006 Sonata and used a Bosch OEM filter I bought over the internet from a Hyundai dealer. It doesn't have the valve in the bottom of the filter like the Hyundai filter did that I removed. An earlier post said the valve kept the oil from draining out of the filter and causing loss of oil to valve train on startup. I'm confused by this explanation since the filter sits vertically on the engine and there is no way that the oil is going to drain out of it. The valve might be a bypass valve if the filter gets clogged, which is usually what is in some filters. Any comments? Tom