Originally Posted By: 2009Edge
The anti drain back valve in the filter does not work. AMSOIL EaO filters have an anti drain back valve that WORKS. A EaO57 is for a 6 cylinder and a EA009 is for a 4 cyl.
It's funny that you mention that, because the only time I've ever had trouble with an ADBV was with an Amsoil EaO20 filter. It was probably a fluke, because I know they're normally good filters. I remember with the EaO it would take a good 3 seconds for the oil pressure light to turn off at start-up, whereas with the Napa I'm using now, it takes between 1-2 seconds. It's been like that with every other filter I've used as well, the EaO was the only anomaly. I've always used 5W-30 so I know it wasn't the grade of the oil, either. At the time I was using the EaO, I was using Amsoil ASL 5W-30.