Reinforced head gasket Opel 1.6 16V Z16LET Z16LER A16LET A16LER A16XER

The Opel engines covered

The A16LEL, A16LER, A16LES, A16LET, A16XER, A16XNT, B16LER, B16LES, B16XER, B16XNT, D16XER, Z16LEL, Z16LER, Z16LET, Z16XER and Z16XNT are 1.6 litre petrol engines with sixteen valves, naturally aspirated or turbocharged. They power the Opel, Vauxhall, Holden, Saab and Westfield models in the compatibility table below, and each takes a single cylinder head gasket.

The original gasket carries part number 55 355 578, or 56 07 895 and 93 186 222 depending on the version. Opel does not publish its bore, thickness or construction. It is sized for standard combustion pressure; when it rises, the clamping load relaxes, the cylinder head lifts slightly and coolant finds its way into a cylinder.

Reinforced cylinder head gaskets

The gasket does only half the sealing job: the other half comes from the fasteners that clamp the head to the block. A composite gasket is permanently crushed beyond 100 N/mm², whereas the 301 stainless steel of MLS gaskets withstands up to 517 N/mm², which is 5 times more, and springs back on every combustion cycle.

This page brings together two part numbers from two competition makers, Athena (Italy) and Cometic (United States), both in multi-layer steel MLS construction. Athena offers the 338286R, 1.0 mm thick for an 80 mm bore; Cometic offers the H1568SP4044S, 1.12 mm thick for an 80.5 mm bore. The engine takes only one gasket: order a single part number, according to the bore and thickness you want.

Technical specifications

Gasket volume is the free space the gasket leaves above each piston. It comes on top of the combustion chamber and lowers the compression ratio; compare only gaskets with the same bore, since the two part numbers on this page do not share one.

Preparation and fitting

Before fitting, check the flatness of the cylinder head and block with a straightedge, and have them resurfaced if needed. Athena and Cometic supply their gaskets already coated: do not add any sealant.

Technical guide

The two constructions offered

Athena MLS Athena MLS Two to five layers of AISI 301 stainless steel, laser cut, then stamped and riveted. Around each cylinder a folded layer, the Gas Stopper, directs the clamping load onto the combustion chamber, while beads close off the water and oil passages. The outer faces are coated: a first coat withstands high temperatures and takes up small imperfections in the block and head, a second, silicone-based coat stops the gasket sticking at strip-down. Athena offers it as its all-steel solution, from the tuned naturally aspirated engine to moderate boost.

Cometic MLS A stack of stainless steel layers, stamped and joined by rivets. The two surface layers carry raised beads around every cylinder and every fluid passage, so the gasket seals with only a moderate clamping load and the bore keeps its round shape. It suits a tuned naturally aspirated engine as well as moderate boost.

Choosing bore and thickness

Gasket bore. The Athena MLS is available here with an 80 mm bore (338286R) and the Cometic MLS with an 80.5 mm bore (H1568SP4044S).

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

Since Opel does not state the original thickness, use a dial gauge to measure how far the pistons stand above the block face, particularly if you choose 1.0 mm: it sets the piston-to-head clearance.

The two brands

	Athena S.p.A. is an Italian maker of gaskets and engine components whose headquarters and main plant are in Alonte, in the Veneto region. The group also has sites in Spain, the United States, Brazil and India. Some car makers fit its multi-layer gaskets as original equipment, and its competition range is designed and built entirely in Italy.
	Cometic Gasket, Inc. was founded in 1989 and is based in Concord, Ohio. It makes gaskets and sealing solutions for engines, and became known for its made-to-order gaskets, cut to the bore and thickness requested. Its production is entirely American, 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 gasket offered (80 mm for Athena, 80.5 mm for Cometic) 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: 55 355 578 ; 56 07 895 ; 93 186 222.

Important: the Cometic H1568SP4044S is only listed for the Z16LET 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 takes over: even under higher combustion pressure it holds its shape instead of being crushed.

Turbo, supercharger or raised compression ratio: in each case the cylinder head gasket is the first weak point of a high-output engine. A reinforced gasket prevents the leak and, above all, the cylinder head removal that follows, which costs far more than the gasket itself.