Reinforced head gasket Audi RS3 8V TT RS 2.5 TFSI DAZA DNWA DNWC DNWB

The Audi engines covered

The 2.5-litre TFSI turbocharged five-cylinder petrol engine, identified by the codes DAZA, DNWA, DNWC and DNWB, powers the Audi TT RS, RS 3 and RS Q3 models listed in the table below.

For these engines the manufacturer lists the standard gaskets 07K 103 383 L and 07K 103 383 AE, and publishes neither their bore, their thickness nor their construction. Each engine takes only one, calibrated for the standard combustion pressure: once that pressure rises, the clamping load weakens, the cylinder head lifts and coolant can reach a cylinder.

Reinforced cylinder head gaskets

The gasket does not seal on its own: sealing also depends on the bolts that clamp the head to the block. A composite gasket takes a permanent set above 100 N/mm² of allowable stress, whereas the 301 stainless steel of the MLX gaskets withstands 517 N/mm², 5 times more, and springs back with each combustion. With the O-Ring, the stainless ring alone seals the combustion chamber, the gasket body closes the water and oil circuits, and the block does not have to be machined.

This page brings together seven references from two competition gasket makers: Athena's O-Ring (330117R), which pairs an aramid-fibre-coated steel sheet with a stainless ring, and six Cometic MLX gaskets, multilayer stainless steel. Every gasket has an 83.5 mm bore and thicknesses run from 1.40 to 2.03 mm, enough to adjust the compression ratio without touching the pistons or the cylinder head. As a rule, the gasket bore chosen is at least 0.5 mm larger than the actual cylinder bore. Each part number is sold individually, one gasket per engine.

Technical specifications

A gasket's volume is the free space it leaves above each piston. It adds to the combustion chamber and lowers the compression ratio; since every gasket here has the same 83.5 mm bore, only the thickness changes that volume, so the figures can be compared directly.

Preparation and fitting

Before fitting, check the flatness of the head and block with a straightedge, and have either one machined if it is out of tolerance. Athena and Cometic gaskets leave the factory ready to fit: do not add any sealant.

Technical guide

The two constructions offered

Athena O-Ring / Cut Ring A steel sheet clad in asbestos-free aramid fibre, with a stainless steel compression ring around each cylinder. The ring concentrates the clamping force on a narrow band, where the sealing happens, and a silicone bead protects the water and oil passages. It is the construction that tolerates the highest pressures, and the only one compatible with a head already prepared with a compression wire.

Cometic MLX A multilayer stainless steel stack whose centre layer, folded with precision, forms a stopper around the combustion chamber. The embossed outer layers seal the oil and coolant passages. Local clamping rises without increasing bore distortion. Worth remembering when boost calls for a tougher all-steel gasket, here in 83.5 mm only.

Choosing bore and thickness

Gasket bore. The Athena O-Ring and the Cometic MLX gaskets all come in 83.5 mm, and in that bore only.

Thickness. For gaskets 07K 103 383 L and 07K 103 383 AE, the manufacturer gives no thickness. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Since the manufacturer gives no original thickness, measure with a dial indicator how far the pistons stand above the block deck, especially if you are aiming for 1.40 mm: it sets the clearance that remains between the piston and the head.

The two brands

	Athena S.p.A. is an Italian maker of gaskets and engine parts, with its head office and main plant in Alonte, in the Veneto region, and other sites in Spain, the United States, Brazil and India. Its multilayer gaskets are fitted by carmakers as original equipment, and its competition range is designed and made entirely in Italy.
	Cometic Gasket, Inc. is an American company founded in 1989 in Concord, Ohio, which designs gaskets and sealing solutions for engines. It made its name with the gasket made to order, at the bore and thickness you specify, and still manufactures everything in the United States from American 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 bore of the original gasket 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: 07K 103 383 L and 07K 103 383 AE.

Important: the references on this page only apply to the DAZA, DNWA, DNWC and DNWB engines: check the engine code of your vehicle before ordering.

Why switch to a reinforced gasket?

Where the original gasket reaches its limit, the reinforced gasket takes over: under a higher combustion pressure, it keeps its shape instead of flattening.

Once an engine gets more boost, a larger turbo or a raised compression ratio, the head gasket is the first part of the upper engine to give way. A reinforced gasket prevents the leak, and the head removal that follows it: it is a gain in reliability before it is a gain in comfort.