Indmar Marine Intake Manifold Gasket – 5.7L Vortec Engine | Part #556099
⚠️ Important: 2 gaskets required per engine — order quantity 2

Ensure a perfect intake seal on your Indmar 5.7L Vortec engine with this genuine Indmar intake manifold gasket. A critical sealing component that sits between the intake manifold and cylinder head — maintaining the correct air/fuel mixture delivery into your engine. A failed intake gasket is one of the most common causes of vacuum leaks, rough running, and coolant loss on the 5.7L Vortec marine engine.

Compatible with: Indmar 5.7L Vortec marine engines fitted to Malibu, Moomba, Supra, and Tige boats. Contact us to verify fitment for your specific model year before ordering.

Why do you need 2 gaskets per engine?
The Indmar 5.7L Vortec uses a dual intake manifold gasket configuration — one gasket per bank of cylinders. This means every intake manifold removal requires two gaskets — one for the left bank and one for the right bank. Never attempt to reuse one old gasket alongside a new one — always replace both at the same time to ensure an even, leak-free seal across the entire intake manifold.

What does the intake manifold gasket do?
The intake manifold gasket seals the junction between the intake manifold and the cylinder heads — one of the most critical sealing surfaces on the entire engine. It must simultaneously:

• Seal the air/fuel charge entering each cylinder
• Contain coolant passages running through the intake manifold
• Withstand constant thermal expansion and contraction cycles
• Resist vacuum pressure and combustion blowback

A failed intake gasket can cause multiple problems simultaneously — making it one of the trickier faults to diagnose without knowing what to look for.

Signs your intake manifold gasket needs replacing:

• Rough idle or vacuum leak hissing noise
• Coolant loss with no visible external leak
• White smoke from the exhaust — coolant entering combustion
• Overheating despite coolant levels appearing normal
• Rich or lean running conditions and fault codes
• Oil contamination in the coolant — or coolant in the oil
• Loss of power or poor throttle response

When should you replace it?
Replace your intake manifold gaskets any time you:

• Remove the intake manifold for any reason
• Notice any of the symptoms listed above
• Carry out a top end engine rebuild or overhaul
• Replace the intake manifold itself
• Service the throttle body or fuel injection components requiring manifold removal

Pro tip: The 5.7L Vortec intake gasket is a known wear item on these engines — particularly on boats that have seen many heat cycles over multiple seasons. If your engine is showing any signs of coolant loss or rough running and you can't find an obvious external cause, the intake gaskets are well worth inspecting before going deeper into the engine.

Remember — order 2 per engine. Add quantity 2 to your cart before checkout.

Pairs perfectly with:

• 985006 – Thermostat Housing Gasket
• 986034 – Thermostat 160° Drilled LT1 & 5.7L F/W
• 866081 – Thermostat Housing Aluminium Full F/W

Features:

• Genuine Indmar OEM part
• Designed specifically for Indmar 5.7L Vortec marine engines
• Seals both air/fuel charge and coolant passages
• Withstands constant thermal cycling in marine applications
• Precision cut for perfect OEM sealing surface fit
• Single use — always replace, never reuse
• 2 gaskets required per engine — sold individually

Part Number: 556099
In stock and shipped fast from Australia 🇦🇺