Engine Lifter Valley Coolant Plate

What Is an Engine Lifter Valley Coolant Plate?

Tucked beneath the intake manifold and sitting directly atop the engine block, the engine lifter valley coolant plate is one of those unsung components that quietly holds a great deal of responsibility. The valley plate is the metal plate below the intake manifold that seals off the top of the engine block "valley" between the cylinder banks. On engines where coolant passages run through this region, the plate also serves as a critical barrier between the cooling system and the rest of the valvetrain — earning it the "coolant plate" designation.

Why the Valley Coolant Plate Matters

The function of the lifter valley plate is to provide a seal and a surface for the intake manifold to rest on, as well as to provide support for the lifters and pushrods. The plate also helps to direct oil flow to the lifters and other engine components. When coolant passages are incorporated, the plate must simultaneously manage two fluid systems — oil and coolant — without allowing either to migrate where it doesn't belong.

Without a functioning lifter valley plate, the engine may experience oil leaks or improper oil flow to the lifters and other engine components, leading to increased wear and potentially catastrophic engine failure. On engines where coolant runs through the valley, a compromised plate can also introduce coolant contamination into the oil — a far more serious problem that can spell the end of an engine if left unaddressed.

Common Applications: OHV and LS-Family Engines

The lifter valley plate is a component found in engines with overhead valve configurations, typically made of aluminum or steel and located between the engine block and the intake manifold, covering the valley between the cylinder heads. General Motors' immensely popular LS engine family is among the most well-known applications for valley plates and covers, making this a particularly relevant part for engine swaps, performance builds, and restoration projects alike.

Coolant flows through this area, and some engines have been known to develop leaks here — making periodic inspection and timely replacement an important part of long-term engine health. Whether you're chasing a coolant leak, refreshing a high-mileage engine, or building a performance motor from scratch, selecting the right valley coolant plate ensures proper sealing, correct oil routing, and a solid foundation for the intake manifold above.

What to Look for When Shopping

• Material: Aluminum plates offer light weight and corrosion resistance, while steel units provide added durability in high-stress applications.
• Engine compatibility: Valley plates are highly application-specific — confirm fitment for your exact engine family (Gen III, Gen IV LS, etc.).
• Integrated features: Some plates include provisions for breathers, PCV ports, or oil fill tubes, which can simplify engine bay routing during a build.
• Sealing system: Check whether the plate requires a separate gasket or relies on a sealant — proper sealing is critical to preventing coolant or oil intrusion.

Top Brands in Engine Lifter Valley Coolant Plates

When it comes to sourcing a reliable engine lifter valley coolant plate, choosing a manufacturer with deep roots in engine technology makes all the difference. Holley is a cornerstone name in American performance engineering, with decades of experience designing components for OHV and LS-based powerplants. Their valley covers and related components are engineered to meet the demands of both street builds and high-performance applications, making them a trusted choice for builders who won't compromise on quality or fitment.