Reinforced cylinder head gasket Ford Focus ST Mondeo S-MAX Kuga 2.0 EcoBoost R9DA R9DB R9DC R9DD TPBA TNBA TNWA TNWB TPWA

The Ford engines covered

The Ford R9DA, R9DB, R9DC, R9DD, TPBA, TNBA, TNWA, TNWB and TPWA petrol engines, of 2.0 litres, are fitted to the Ford Focus III, Mondeo IV, Galaxy II, S-MAX and Kuga II models listed below.

The original gasket part numbers for these engines are 5149932 and 1 682 135. Ford publishes neither the bore, nor the construction, nor the thickness. It is designed for standard combustion pressure: as that pressure rises, the clamping load relaxes, the cylinder head lifts and coolant seeps into a cylinder.

Reinforced cylinder head gaskets

The head gasket does not seal on its own: the fasteners that clamp the head onto the block matter just as much. Above 100 N/mm², a composite gasket is crushed for good, whereas the 301 stainless steel of MLS gaskets withstands 517 N/mm², 5 times more, and recovers its shape at every combustion.

This page brings together the part numbers of Cometic, an American maker of racing gaskets, for a single construction: the multi-layer steel MLS. Every gasket has a 89 mm bore and thicknesses from 0.69 to 3.56 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

The volume of a gasket is the space it leaves open above each cylinder. It is added to the combustion chamber and lowers the compression ratio the more it grows. Compare this figure only between gaskets of the same bore.

Preparation and fitting

Before fitting, lay a straight edge across the head and block faces to check they are flat, and have them resurfaced if necessary. Do not add any sealing paste: Cometic gaskets are delivered already coated.

Technical guide

The construction offered

MLS Cometic Stainless steel layers, stamped and joined with rivets. The outer layers carry active beads around every cylinder and every fluid passage. A moderate tightening torque is enough to seal, and the bore distorts very little. This versatile design covers everything from the tuned naturally aspirated engine to moderate boost.

Choosing bore and thickness

Gasket bore. The Cometic MLS is offered in 89 mm (C15317), in that bore only.

Thickness. The thickness of the original gasket is not published by Ford. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Should you choose a thickness under the original one, read with a dial gauge how high the pistons rise above the block deck: the reading gives the clearance remaining between piston and head.

The brand

Cometic Gasket, Inc. is an American manufacturer of engine gaskets and sealing solutions, established in 1989 in Concord, Ohio. It specialises in the custom gasket, cut to the bore and thickness required. Its entire output stays in the United States and uses 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, not published by Ford 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: 5149932 and 1 682 135.

Important: the part numbers on this page fit only the R9DA, R9DB, R9DC, R9DD, TPBA, TNBA, TNWA, TNWB and TPWA engines: check your vehicle's engine code before placing an order.

Why switch to a reinforced gasket?

Once the original gasket has reached its limit, the reinforced gasket takes over: under higher combustion pressure it holds its shape and is not crushed.

Add a turbo or a supercharger, or increase the compression ratio, and the head gasket becomes the most heavily stressed part of the top end. A reinforced gasket avoids the leak and the cylinder head removal that would follow.