Wix Filter/NapaGold Oil Filter vs Purolator
- Purolator uses a leaf spring rather than a coil spring; the leaf spring must always seat properly onto the end cap. Additionally, a leaf spring can bend under high pressures.
- Purolator uses metal end caps rather than the fiberboard end caps.
- The filter media inside the Purolator was crimped to itself, rather than glued, and a string was loosely tied around the media.
- Purolator uses a phenolic resin which helps to bind the media and protect during high temperatures.
- The center tube of the Purolator filter is a spot-welded, straight seam; other brands use a spiraled center tube for better flow.
- The Purolator filter uses a silicon anti-drain back valve which is less likely to break down than the nitrile rubber valves. The anti-drain back valve is used to prevent oil from draining back to the crankcase after shutdown.
- We found excessive amounts of glue over the end caps.
- The Purolator was the shortest of all the filters.
- The Purolator had the most number of pleats at 67, but the pleats were wavy.
- The Purolator filter tied the Bosch filter with the longest media at just over 101 inches.
- The Purolator filter had the most media area at 384 square inches.