Cometic Multi-layer Steel Head Gasket, BMW N55/S55

This Cometic MLS Head Gasket is designed to replace BMW part numbers 11127599212, 11127599213, 11127849620, and 11127849621, specifically for the N55B30 and S55B30 turbocharged inline-six engines. 

Composed of multiple layers of embossed coated and uncoated stainless steel, MLX gaskets are specially designed to conform to the surfaces of the cylinder head and engine block on the first heat cycle, creating a chemical bond via Cometic's proprietary coatings. These coatings provide a micro-seal for fluids against the head and block surface. 

The layers of the MLX gasket act as a spring, protecting against blowout and increasing active seal height by compensating for increased head lift. 

MLX Head Gaskets are different from MLS because they feature an extra,specialized 'stopper' fold-over layer. This layer provides a torque limiting surface that prevents yielding of the combustion seal. 

It's important to note that MLS/MLX head gaskets are not compatible with engines that have O-rings or receiver grooves around the cylinder bores. These gaskets require smooth and flat surfaces to seal properly.

Installation instructions:

1. Make sure that the engine block and cylinder head surfaces are clean, flat, and free from any debris, oil, or coolant.

2. Install the MLX gasket on the engine block and ensure that it is properly aligned. Avoid twisting or bending the gasket during installation.

3. Place the cylinder head on top of the gasket and install the head bolts or studs in their correct positions.

4. Follow the manufacturer's recommended torque specifications and tighten the bolts or studs in the proper sequence to ensure even clamping force across the gasket.

5. After the initial tightening, re-torque the head bolts or studs after the engine has been started and then allowed to cool to room temperature. This will ensure that the gasket is properly seated and compressed.

6. It is recommended to not use any additional sealant on the MLX gasket, as it is already coated with a Viton rubber sealant. Using additional sealant can hinder the performance of the gasket.