Reinforced head gasket Mercedes-Benz A45 CLA45 GLA45 AMG M133.980

The Mercedes-Benz engines covered

The 2.0 litre turbocharged petrol four-cylinder M133.980, of 1991 cm³, powers the Mercedes-Benz A-Class (W176), CLA Coupé (C117), CLA Shooting Brake (X117) and GLA-Class (X156) in AMG 45 4Matic form, from 2013 to 2019. This page covers this single engine code.

The original gasket is listed as 133 016 11 00 according to the TecDoc parts database; the manufacturer publishes neither its thickness nor its construction. It is rated for the standard combustion pressure; as soon as that rises, the clamping load fades, the head lifts and coolant seeps into a cylinder.

Reinforced cylinder head gaskets

Sealing does not rest on the gasket alone: the fasteners clamping the head to the block contribute as much. The stainless ring of the O-Ring keeps its shape after every combustion. On this engine, new bolts at every refit limit head movement and leaks.

This page presents the part numbers from Athena, an Italian maker of racing gaskets, in one construction only: the O-Ring, a steel sheet dressed with aramid fibre and ringed with a stainless steel ring. Both part numbers have a bore of 83.6 mm and thicknesses of 1.00 and 1.30 mm. They are sold individually: a single gasket fits one engine.

Technical specifications

Gasket volume is the space it keeps free above each cylinder. It comes on top of the combustion chamber and therefore reduces the compression ratio. Only a comparison between gaskets of the same bore makes sense. Here, the bore offered is 83.6 mm.

Preparation and fitting

Before fitting, check the flatness of the head and of the block with a straightedge, then have them machined if needed. Athena supplies these gaskets ready to fit: apply no sealing paste. Neither the head nor the block needs any modification.

Technical guide

The construction offered

Athena O-Ring A steel sheet coated with asbestos-free aramid fibre, in which each cylinder is encircled by a stainless steel compression ring. The ring carries the clamping load onto a narrow band, exactly where sealing is won or lost, while a silicone bead keeps the water and oil circuits apart. Within the range, it is the construction that best withstands high pressures.

Choosing bore and thickness

Gasket bore. The Athena O-Ring exists in 83.6 mm (330158R and 330159R), with no other bore.

Thickness. The manufacturer does not publish the thickness of the original gasket of this engine. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Since the original thickness is not published, measure with a dial gauge how far the pistons stand above the block, especially if the removed gasket is thicker than 1.00 mm: that value gives the clearance left between piston and head. On this engine, the measurement is taken with the head removed.

The brand

An Italian maker of gaskets and engine parts, Athena S.p.A. is based in Alonte, in the Veneto, where its head office and main plant stand. The group also runs sites in Spain, the United States, Brazil and India. Its multi-layer gaskets are fitted by car makers as original equipment, and its competition range is entirely designed and made in Italy. Part numbers 330158R and 330159R are the ones on this page.

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 83.6 mm bore of the gaskets 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: 133 016 11 00.

Important: the part numbers on this page suit the M133.980 engine of the Mercedes-Benz AMG 45 models: check the engine code of your A-Class, CLA or GLA before ordering.

Why switch to a reinforced gasket?

When the standard gasket can no longer keep up, the reinforced gasket steps in: at higher combustion pressure it keeps its shape and does not get crushed. The Mercedes M133.980 engine finds here gaskets with an 83.6 mm bore.

When power climbs thanks to a turbo, a supercharger or a raised compression ratio, the head gasket is the first part of the top end to suffer. A reinforced gasket rules out the risk of a leak and the cylinder head removal that would follow, with the labour and parts cost of doing the job twice. This holds for the A 45, CLA 45 and GLA 45 as for any hard-driven engine.