27-99757 Exhaust Manifold Gasket for MerCruiser Volvo OMC Crusader 4.3 V6 | JLM Marine

Exhaust Manifold Gasket for MerCruiser, Volvo, OMC & Crusader 4.3 V6 Engines

This high-quality exhaust manifold gasket is engineered for GM 4.3 V-6 marine engines used across MerCruiser, Volvo Penta, OMC, and Crusader stern drives. Designed to meet and exceed factory specifications, this gasket provides a reliable seal for exhaust manifold mounting applications.

This aftermarket replacement directly crosses to MerCruiser 27-99757, Volvo 3853412, OMC 856116, and Crusader 97498, along with multiple aftermarket equivalents. It ensures proper sealing and durability under demanding marine conditions.

• Direct fit for 4.3L V6 marine engines
• Manufactured to OEM specifications for reliable performance
• Compatible with multiple stern drive brands

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

This gasket fits all 4.3L GM V-6 marine engines installed in MerCruiser, Volvo Penta, OMC, and Crusader stern drive applications.

Technical Specifications

Package Contents

• 1 × Exhaust Manifold Gasket (27-99757)

Installation Guide

1. Disconnect the battery and allow the engine to cool completely before beginning work.
2. Remove the exhaust manifold bolts and carefully separate the manifold from the cylinder head.
3. Thoroughly clean both the manifold and cylinder head mating surfaces, removing all old gasket material and debris.
4. Inspect the manifold and head for warping, cracks, or damage; resurface or replace if necessary.
5. Position the new gasket onto the cylinder head, aligning all bolt holes carefully.
6. Reinstall the exhaust manifold, ensuring proper alignment with the gasket.
7. Hand-tighten all manifold bolts first, then torque them to the manufacturer's specifications in the recommended sequence (typically center-out).
8. Reconnect any exhaust components, hoses, and fittings that were removed.
9. Reconnect the battery and start the engine, checking for exhaust leaks around the manifold.
10. Allow the engine to reach operating temperature and recheck for any signs of leakage.

Troubleshooting & FAQ

Q: How do I know if my exhaust manifold gasket needs replacing?
A: Common signs include exhaust leaks (visible steam or soot), unusual exhaust noise or hissing near the manifold, decreased engine performance, or overheating. Inspect the gasket area during routine maintenance for deterioration or damage.

Q: Will this gasket fit both port and starboard manifolds?
A: Yes, this gasket is designed to fit exhaust manifolds on both sides of 4.3L V-6 engines. Verify your application against the cross-reference numbers listed above.

Q: How often should I replace the exhaust manifold gasket?
A: Replace the gasket whenever the exhaust manifold is removed for service or repair. Regular inspection during engine maintenance is recommended, especially in high-hour or saltwater applications.

Q: Can I reuse the old gasket if it looks okay?
A: No, exhaust manifold gaskets are designed for single use. Reusing a gasket can result in improper sealing and exhaust leaks. Always install a new gasket when reassembling.

Q: What's the difference between OEM and aftermarket gaskets?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.