27-815528 Exhaust Manifold Gasket for MerCruiser OMC Volvo Penta MCM 3.0L MCM 3.0LX | JLM Marine

27-815528 Exhaust Manifold Gasket for MerCruiser OMC Volvo Penta MCM 3.0L MCM 3.0LX

This Exhaust Manifold Gasket is engineered for MerCruiser MCM 3.0L (1998 & newer) and MCM 3.0LX (1990-1997) engines, as well as OMC Cobra GM 3.0L 4-cylinder and Volvo Penta GM 3.0L exhaust manifolds with small exhaust ports. It delivers a reliable seal to prevent exhaust leaks and ensure optimal engine performance.

This gasket directly replaces Mercury MerCruiser 27-815528, OMC Cobra 03853256, Volvo Penta 3853256, and Sierra 18-0680, providing broad cross-brand compatibility for your 3.0L GM marine engine.

• Fits MerCruiser, OMC Cobra, and Volvo Penta 3.0L GM engines
• Designed for exhaust manifolds with small exhaust ports
• Direct OEM-spec replacement for reliable sealing

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.

Technical Specifications

Package Contents

• 1 × Exhaust Manifold Gasket

Installation Guide

1. Disconnect the battery and allow the engine to cool completely before beginning work.
2. Remove the exhaust manifold bolts and carefully lift the manifold away from the engine block.
3. Thoroughly clean all gasket surfaces on both the manifold and cylinder head, removing old gasket material and debris.
4. Inspect the manifold and cylinder head for cracks, warping, or damage; resurface or replace if necessary.
5. Position the new gasket onto the cylinder head, aligning all bolt holes and port openings carefully.
6. Reinstall the exhaust manifold, ensuring proper alignment with the gasket and mounting studs.
7. Hand-tighten all manifold bolts first, then torque to manufacturer specifications in a crosswise pattern.
8. Reconnect any exhaust components, hoses, or hardware that were removed during disassembly.
9. Reconnect the battery and start the engine, checking carefully for exhaust leaks around the gasket.
10. Allow the engine to reach operating temperature and re-inspect all connections for proper sealing.

Troubleshooting & FAQ

Q: How do I confirm this gasket fits my engine?
A: Cross-reference your engine model and year in the compatibility table above. Verify your OEM part number matches Mercury 27-815528, OMC 03853256, Volvo Penta 3853256, or Sierra 18-0680, and confirm your exhaust manifold has small exhaust ports.

Q: What are the signs that my exhaust manifold gasket needs replacement?
A: Common symptoms include visible exhaust leaks at the manifold joint, hissing or ticking noises from the engine, reduced performance, or strong exhaust odor in the engine compartment. Inspect the gasket area regularly for carbon buildup or moisture.

Q: Can I reuse the old gasket during reassembly?
A: No, exhaust manifold gaskets are designed for one-time use. Reusing a compressed or torn gasket will result in leaks and poor sealing. Always install a new gasket when servicing the exhaust manifold.

Q: How often should I replace the exhaust manifold gasket?
A: Replace the gasket whenever you remove the exhaust manifold for service or repair. Inspect it annually for signs of leakage, especially on engines operating in saltwater or high-heat conditions.

Q: Is this an OEM or aftermarket part?
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.