Reinforced head gasket VW Audi 1.8 2.0 2H GX HT JH JN PF PG RD RV PL 9A

The Volkswagen and Audi engines covered

The inline four-cylinder petrol engines of 1.8 litres (2H, GX, HT, JH, JN, PF, PG, RD, RV and PL) and 2.0 litres (9A) from the Volkswagen group make up this family: the PL and the 9A have 16 valves and the PG exists as the G60. They power the Volkswagen Golf I and II, Jetta I and II, Passat B2, B3 and B4, Scirocco, Corrado, Caddy I, Santana and Fox, as well as the Audi 80 B2 and B3 and the Audi Coupé B2 in the table below. One cylinder head covers all four cylinders: the gasket is sold singly, one per engine.

The manufacturer lists the standard gasket as 026 103 383 K, and 037 103 383 for the PG; it publishes neither the bore, nor the thickness, nor the construction of these gaskets. They are sized for the original combustion pressure: beyond it the clamp load relaxes, the head lifts and coolant passes into a cylinder.

Reinforced cylinder head gaskets

The gasket is not everything: the fasteners that clamp the head to the block matter as much as it does. Above 100 N/mm² of stress, a composite gasket settles for good; the 301 stainless steel of MLS gaskets withstands 517 N/mm², 5 times more, and recovers its shape at every combustion.

This page gathers the part numbers of a single competition manufacturer, Cometic, in multi-layer MLS construction, with three gasket bores: 83, 84 and 85 mm. Thicknesses run from 0.69 to 3.56 mm, enough to set the compression ratio without touching pistons or 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

The volume of a gasket is the free space it leaves above each piston. It adds to that of the combustion chamber and lowers the compression ratio. The comparison only makes sense between gaskets of the same bore, here 83, 84 or 85 mm.

Preparation and fitting

Before fitting, run a straight edge over the head and the block to check their flatness, and have any warped surface ground. Apply no sealing compound: Cometic supplies its gaskets already coated and excess compound would upset the clamping load.

Technical guide

The construction offered

Cometic MLS Embossed stainless steel sheets, stacked and riveted to one another. The outer sheets carry active raised beads around each cylinder and each fluid passage. A moderate clamping load is enough to seal and the bore distorts little: a versatile construction, from the tuned naturally aspirated engine to reasonable boost.

Choosing bore and thickness

Gasket bore. The Cometic MLS comes in 83 mm (C4247), in 84 mm (H0950SPA070S) and in 85 mm (C4246).

Thickness. The manufacturer gives no thickness for its standard gaskets: only the measurement of the removed gasket counts. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

As the standard thickness is not published, use a dial gauge to read how far the pistons stand above the block deck: this figure gives the clearance left between piston and head, above all if you choose a thickness below that of the removed gasket.

The brand

Cometic Gasket, Inc., an American maker of gaskets and sealing solutions for engines, was founded in 1989 in Concord, Ohio. Its reputation rests on the made-to-order gasket, cut to the bore and thickness required and built entirely in the United States 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 bore of the gaskets offered (83, 84 and 85 mm) 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: 026 103 383 K ; 037 103 383.

Important: the gaskets on this page are listed for the 1.8 litre and 2.0 litre engines of the survey below, at Volkswagen and Audi. For any other vehicle, check the engine code before ordering.

Why switch to a reinforced gasket?

When the standard gasket is no longer enough, the reinforced gasket takes over: under higher combustion pressure, the stainless steel of the MLS sheets does not crush and the gasket keeps its shape.

An engine fitted with a turbo, a supercharger or a higher compression ratio puts the head gasket to the test first, as the weakest link of the top end. A reinforced gasket spares you the leak and the head removal that follows, a job far more expensive than the part: better to fit it at the build stage.