Reinforced cylinder head gasket Mercedes 190 E 2.5-16 M102.990 M102.991 M102.992

The Mercedes-Benz engines covered

The 2.5-litre 16-valve M102.990, M102.991 and M102.992 engines power the Mercedes-Benz 190 E 2.5-16 (W201) and its Evolution and Evolution II versions, listed below.

The original gasket of these engines carries the part numbers 102 016 09 20, 102 016 10 20, 102 016 11 20 and 102 016 26 20. Mercedes-Benz publishes neither its bore, nor its thickness, nor its construction. It is sized for standard combustion pressure; as soon as it rises, the head loosens, lifts and coolant finds its way into a cylinder.

Reinforced cylinder head gaskets

Sealing does not rest on the gasket alone: the bolts or studs that press the head onto the block count just as much. The CFM-20 pairs a galvanized steel core with a soft asbestos-free compound that fills the small flaws of the sealing faces.

This page offers one part number from the American maker Cometic, a specialist in racing gaskets: the H3311SP2059PR, in CFM-20, with a 97 mm bore and a thickness of 1.50 mm, with copper rings around the cylinders. It is sold individually.

Technical specifications

A gasket's volume is the void it leaves above each piston. That void adds to the combustion chamber and reduces the compression ratio; only gaskets of the same bore can be compared.

Preparation and fitting

Before fitting, run a straightedge over the head and the block to check their flatness, and have resurfaced whichever part requires it. Cometic itself checks the flatness of each CFM-20 gasket before shipping it.

Technical guide

The construction offered

Choosing bore and thickness

Gasket bore. The Cometic CFM-20 is offered in 97 mm (H3311SP2059PR), with no other bore.

Thickness. Mercedes-Benz gives no thickness for the original gasket of these engines. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

With no published original thickness, read with a dial gauge how far the pistons protrude above the block's gasket face, above all if the removed gasket is thinner than 1.50 mm: that figure gives the clearance left between piston and head.

The brand

Founded in 1989 in Concord, Ohio, Cometic Gasket, Inc. is an American maker of gaskets and sealing solutions for engines. Its reputation rests on the gasket made to measure, at the bore and thickness requested; all production takes place 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 97 mm bore of the gasket 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: 102 016 09 20, 102 016 10 20, 102 016 11 20 and 102 016 26 20.

Important: the part number on this page applies to the M102.990, M102.991 and M102.992 engines of the table above: read your vehicle's engine code and check the 97 mm bore before ordering.

Why switch to a reinforced gasket?

Once the original gasket has reached its limit, this CFM-20 takes over: the steel core absorbs combustion pressure without deforming, and the soft compound on each face matches the small irregularities of the head and block.

An engine pushed close to its limits often loses its head gasket first. The reinforced gasket avoids that leak and costs much less than the head removal that would follow, with no long spell off the road. Choosing it at the first rebuild also spares the cost of a second teardown.