GJYSYP Oil Valley Seal Plugs for GM Gen IV/Gen V DOD/AFM Valley Covers — 8‑Piece Kit, 4 mm Removable Thread

GJYSYP Oil Valley Seal Plugs are an 8-piece kit designed to plug AFM/DOD oil passages on genuine 2005–2019 Gen IV and Gen V valley covers, enabling conversion to a conventional LS-style lifter oiling setup.

These precision-fit plugs are made for GM applications that use factory DOD/AFM valley covers on engines such as L99, L83, L86, LT1, LT4, LT5 and other LSX/LT variants in 4.8L, 5.3L, 6.0L and 6.2L displacements. They seal the oil under the VLOM plate and allow owners converting away from AFM/DOD lifters to stop oil feed into the stock AFM tappet passages. The kit includes eight plugs that tap gently into the factory oil holes and feature a removable 4 mm x 0.7 threaded top for straightforward extraction if needed.

How do these plugs work with a DOD/AFM valley cover?

The plugs are pressed into the OEM oil passage holes in genuine DOD/AFM valley covers to block oil flow to AFM components. They sit flush with the bottom edge so they don’t protrude into the valley and provide a solid mechanical seal for the converted oiling circuit.

• Eight plugs sized for factory AFM/DOD oil passages.
• Gently tapped into place until flush with the cover bottom edge.
• 4 mm x 0.7 top thread for removal without prying or drilling.
• Intended only for genuine OEM DOD/AFM valley covers, not aftermarket covers.

Will these fit my engine model and valley cover?

These plugs are compatible with Chevrolet, GM, Oldsmobile and Cadillac engines using genuine 4th- and 5th-generation DOD/AFM valley covers from 2005–2019. They are not universal — aftermarket or non-genuine valley covers have different hole sizes and profiles, so fitment is not assured.

• Works with Gen IV (2005–2018) and Gen V (2014–2019) genuine DOD/AFM covers.
• Compatible engine families: L99, L83, L86, LT1, LT4, LT5 and other LSX/LT variants.
• Designed for 4.8L, 5.3L, 6.0L and 6.2L displacements common in these covers.
• Do not use with aftermarket or modified valley covers; they won’t seat correctly.

What is involved in installing and removing the plugs?

Installation is a simple press-fit operation: gently tap the plug into the oil hole until it sits flush. If you need to remove a plug later, the 4 mm x 0.7 threaded top accepts a tool to back the plug out without damaging the cover.

• Tap gently with a soft-faced tool until flush with the valley surface.
• If fit feels loose, freezing the plugs for one hour may improve the tight fit before installation.
• Removal via 4 mm x 0.7 threaded hole prevents destructive extraction methods.
• Recommended for conversions from AFM/DOD to standard LS/LS7 lifter setups.

Are there special care or warranty details I should know?

These plugs are made for a tight, lasting fit in OEM valley covers and should be inspected during installation to ensure proper seating. GJYSYP backs the product with quality inspection and customer support if any fitment or material issues arise.

• Inspect each plug for full seating and flush finish after installation.
• Avoid installing in non-genuine covers to prevent oil leakage or improper fit.
• GJYSYP offers post-sale support and warranty assistance for purchase issues.
• If gaps occur, follow the suggested freezing step before trying installation again.

Who is this for: The GJYSYP Oil Valley Seal Plugs suit mechanics, engine builders and enthusiasts converting AFM/DOD systems to conventional lifter oiling on eligible GM Gen IV and Gen V engines. If you have a genuine DOD/AFM valley cover and plan to remove AFM/DOD components or swap to a traditional LS-style lifter set-up, this eight-piece kit provides the OEM-specific plugs needed to reliably seal the valve-cover oil passages. Do not purchase this kit for aftermarket or modified valley covers — check your cover is a genuine OEM DOD/AFM part before ordering.