Car Engine Seals Exhaust Manifold Gasket 18407506778 For BMW 320i 328i 330i 428i 430i X3 xDrive28i 540i 740i

1. Product Overview

The Exhaust Manifold Gasket (PN: 18407506778) is a high-performance sealing component designed specifically for BMW vehicles. It ensures an airtight seal between the exhaust manifold and the cylinder head, preventing exhaust gas leaks, maintaining backpressure, and optimizing engine efficiency.

Key Features:

• Material: Multi-layer steel (MLS) or graphite-impregnated stainless steel (varies by model) for heat resistance up to 1,500°F (815°C).

• Precision Fit: OEM-equivalent dimensions for perfect alignment with BMW engine blocks.

• Anti-Blowout Design: Reinforced edges resist thermal cycling and mechanical stress.

• Emissions Compliance: Prevents exhaust leaks to meet Euro 5/6 and EPA standards.

3. Applications & Benefits

Purpose:

• Seals the exhaust manifold to the cylinder head.

• Prevents exhaust leaks, which can cause:

  • Loss of engine power.

  • Increased emissions (O2 sensor errors).

  • Loud exhaust ticking/whistling noises.

Ideal For:

• BMW models with turbocharged engines (common in 3-Series, 5-Series, X3, X4).

• High-mileage vehicles (replacement recommended at 80,000–120,000 miles).

4. Manufacturing Process

1. Material Selection: High-grade stainless steel or graphite composite.

2. Laser Cutting: Precision-cut for exact flange contours.

3. Heat Treatment: Tempered to resist warping under extreme temperatures.

4. Quality Control: Pressure-tested to 30 psi (simulating exhaust backpressure).

5. Installation Guide

Tools Required:

• Torque wrench (calibrated to Nm spec).

• New manifold bolts (BMW recommends one-time-use bolts).

• Gasket scraper & brake cleaner (for surface prep).

Steps:

1. Disconnect battery and remove heat shields.

2. Unbolt exhaust manifold (start from outer bolts inward).

3. Clean mating surfaces thoroughly (no old gasket residue).

4. Install new gasket dry (no sealant needed).

5. Torque bolts in cross pattern to BMW’s specification.

⚠️ Warning: Overtightening can crush the gasket, causing leaks!

6. Vehicle Compatibility Table

(For full compatibility, verify with VIN or consult BMW EPC.)

7. FAQ

Q: Does this fit the N55 engine?
A: No, this part is for N20/N26/B48/B58 engines. N55 uses a different gasket (PN: 18407546379).

Q: Can I reuse the old bolts?
A: No—BMW specifies TTY (Torque-to-Yield) bolts for one-time use only.

Q: Symptoms of a failing exhaust manifold gasket?
A: Hissing noise under acceleration, sulfur smell, or check engine light (P0420/P0430).

Q: Ceramic coating recommended?
A: Optional for track cars—reduces heat soak but not required for street use.