Cometic C4349-040 MLS Cylinder Head Gasket Bore BMW - 86mm M42B18/M44B19

The Cometic C4349-040 is a precision-engineered Multi-Layer Steel (MLS) cylinder head gasket designed specifically for BMW M42B18 and M44B19 engines, featuring an 86mm bore and .040 inch (1.0mm) compressed thickness. This 3-layer gasket utilizes round bore construction to deliver exceptional sealing performance in high-output engine applications.

Advanced MLS Construction:

• Comprised of three layers of stainless steel for increased strength, rebound ability, and corrosion resistance
• Outer layers embossed and coated with Viton fluoroelastomer rubber material, heat resistant to 250°C (482°F)
• Center shim layer features uncoated stainless steel construction
• Load-controlled embossments conform load distribution across the sealing area, requiring less clamp load and reducing bore distortion

Key Benefits:

• Ideal for both aluminum-to-aluminum and aluminum-to-cast iron block combinations, withstanding shearing forces between dissimilar materials
• No sealants or re-torque required
• Prevents blow-outs in high cylinder pressure applications as embossed layers act as a spring to compensate for head lift
• Specialized coating creates a chemical bond to cylinder head and block surfaces on first heat cycle

This gasket replaces BMW OEM part numbers 11121721546, 11121721547, 11121721550, and 11121721551. Note: MLS head gaskets cannot be used with motors that have O-rings or receiver grooves around cylinder bores, as they require smooth and flat surfaces to seal properly.

Specifications:

• Part Number: C4349-040
• UPC: 191070054250
• Material: Multi-Layer Steel (MLS)
• Compressed Thickness: .040 inch (1.0mm)
• Bore Size: 86mm (3.386 inches)
• Bore Shape: Round
• Number of Layers: 3