Reinforced head gasket Subaru 2.0 EJ205

The Subaru engines covered

The EJ205 petrol engine of 2.0 litres powers the Subaru Forester and Impreza as well as the Saab 9-2X, detailed below.

The original gasket carries part number 11044-AA482. Subaru publishes neither its bore, nor its thickness, nor its construction. Designed for the standard combustion pressure, it lets go when that pressure rises: the clamping force relaxes, the cylinder head gapes slightly and coolant seeps into a cylinder.

Reinforced cylinder head gaskets

Sealing does not rest on the gasket alone: the fasteners that clamp the cylinder head to the block account for half of it. A composite gasket stays crushed for good beyond 100 N/mm² of stress; the 301 stainless steel of MLX gaskets withstands 517 N/mm², 5 times more, and regains its shape at every combustion.

This page gathers the three part numbers of the American maker Cometic, a specialist in competition gaskets, in a single construction: MLX. They have a bore of 93.5 mm or 93 mm; the thickness is 0.81 mm, 1.04 mm or 1.12 mm. The gasket is always slightly wider than the cylinder: by convention, at least 0.5 mm more on the bore. Each part number is sold individually: one gasket per engine.

Technical specifications

A gasket's volume is the room it leaves free above each cylinder. That room adds to the combustion chamber and lowers the compression ratio; only gaskets of the same bore are compared.

Preparation and fitting

Before fitting, check with a straight edge that the cylinder head and block are flat, and have them machined if necessary. Cometic supplies this gasket coated: apply no sealing paste.

Technical guide

The construction offered

Cometic MLX Several stamped and riveted stainless steel layers, with a folded centre layer forming a stopper around the combustion chamber, and a high-temperature coating. Local clamping rises without the bore distortion increasing. It is the strongest of the all-steel gaskets, to be chosen for high boost levels.

Choosing bore and thickness

Gasket bore. The Cometic MLX comes in 93.5 mm (C4590-032 and C4590-044) and in 93 mm (C4590-041).

Thickness. Subaru gives no thickness for the original gasket. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

As the original thickness is not published, use a dial gauge to measure how far the pistons stand above the block face, notably to aim for 0.81 mm: this reading gives the clearance left between piston and cylinder head.

The brand

Cometic Gasket, Inc. is an American company founded in 1989 in Concord, Ohio, that designs and makes gaskets and sealing parts for engines. Its image rests on the made-to-measure gasket, cut to the bore and thickness requested, from American raw materials.

Advantages over the original gasket

When a reinforced gasket becomes necessary

• Adding forced induction, or raising boost on an already turbocharged engine
• Cylinder rebored beyond what the 93.5 mm and 93 mm bores of the gaskets offered covers
• Looking for a compression ratio different from standard, higher or lower
• Engine that has already lost its gasket, or is consuming coolant
• Competition use, where the gasket goes through repeated temperature rises

Vehicle compatibility

OEM part number: 11044-AA482.

Important: the part numbers on this page suit the EJ205 engine: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limit, the reinforced gasket carries on: even under higher combustion pressure, it does not settle and keeps its shape.

With a turbo, a supercharger or a raised compression ratio, the head gasket is the first element to let go in the top end. The reinforced gasket avoids the leak, then the cylinder head removal that follows, an operation far costlier than the part.