Does anyone know of additional details regarding various manufacturers' warranties for oil filters? As far as I can tell, Wix provides the clearest warranty, covering damage to the engine if their filter fails. NAPA Gold+Silver provides what looks like a rebranded Wix warranty. O'Reilly's Microgard provides a warranty which appears only to cover their filter (not the engine?) if it fails? I couldn't find any details about Fram's warranty coverage.