At the FRAM® Proving Grounds, our engineers test every part of the filter to help make sure failure isn't a part of your engine's life. The Valve Test is a torturous test stand where the focus is on just one component of the oil filter, the relief valve. When you start up an engine on a cold day, the oil might be fairly viscous. The oil should go through the filter media. But if it's too viscous, the pressure can build up across the filter media. And that's where the relief valve comes in. The r