The CAT 1R-1807 oil filter was designed to function vertically so it lacks an anti-drain-back valve. When the CAT oil filter is mounted on a Duramax it is angled horizontally. Without the anti-drain-back valve, dirty oil flows back into the internals every time the engine is shut off.

PPE recognized the need for a better filter product made specifically for the Duramax engine. Building on the platform of better performance, PPE increased the quality in every category compared to stock and addressed the shortcomings of the CAT oil filter.

If you had installed the CAT adapter now you can now easily switch back and get superior filtration with the PPE Premium High-Efficiency Oil Filter using this OEM adapter replacement.

The PPE Oil Filler Adapter works with the brand new Inchordnance-style InchSpecial Issue Premium H.E. Oil Filter (114000560) and the classic black Premium High-Efficiency Oil Filter (114000550) for the GM 6.6L Duramax. If you have not installed the CAT adapter the PPE Premium Oil Filters thread right to the stock mating surface. No adapter needed.

GM Equivalent P/N:97225870