Reinforced head gasket Peugeot Citroën 2.0 16V EW10 XU10J4R

The Peugeot and Citroën engines covered

The petrol engines EW10J4, EW10J4S, EW10D and XU10J4R, PSA two-litre sixteen-valve four-cylinders, are the engines covered by this page; the NGK code RFN designates the EW10J4. They power Peugeot 206, 306, 307, 406, 407, 605, 607, 806, 807 and Expert and Citroën C4, C5, C8, Xsara, Xantia, XM, Evasion and Jumpy models, listed in the compatibility table below.

Four original gaskets are fitted to these engines: 0209.Z3, 0209.EP and 0209.EQ for the EW10 family, 0209.N6 for the XU10J4R. Peugeot and Citroën publish neither their bore, nor their thickness, nor their construction. They are sized for standard combustion pressure: as soon as it rises, the clamping load drops, the head lifts and coolant passes into a cylinder.

Reinforced cylinder head gaskets

It is the head studs or bolts that provide half of the sealing on their own: the gasket never works alone. A composite gasket is crushed for good from 100 N/mm², whereas the 301 stainless steel of an MLS gasket resists 517 N/mm², five times more, and regains its shape with every combustion.

This page groups two part numbers from Athena, an Italian maker of racing gaskets, for a single construction: the multi-layer steel MLS. Both have a 86.0 mm bore and differ only in thickness, 1.0 or 1.3 mm. 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

Gasket volume is the room it leaves free above each cylinder. It adds to the combustion chamber and lowers the compression ratio; as both part numbers share the same bore, the 1.3 mm gasket lowers the ratio more than the 1.0 mm one.

Preparation and fitting

Before refitting, check head and block flatness with a straightedge and have them resurfaced if needed. The Athena gasket is supplied with its coating: do not add any sealant to it.

Technical guide

The construction offered

Athena MLS An assembly of two to five AISI 301 stainless steel sheets, laser cut, pressed and then riveted. Around each cylinder, a folded sheet, the Gas Stopper, transfers the clamping force onto the combustion chamber; raised reliefs separate the water and oil circuits. Two coatings cover the faces: one withstands high temperatures and fills small surface flaws on the block and head, the other, in silicone, prevents sticking at removal. It is Athena's all-steel answer, from a prepared naturally aspirated engine to moderate forced induction.

Choosing bore and thickness

Gasket bore. The Athena MLS is offered in 86.0 mm only (338265R and 338266R).

Thickness. Peugeot and Citroën do not give the thickness of the original gasket. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

As the original thickness is not published, use a dial gauge to measure how far the pistons stand proud of the block face, especially if you are aiming at 1.0 mm: that figure fixes the distance left between piston and head.

The brand

Athena S.p.A. is an Italian company specialising in gaskets and engine parts. It has its head office and large factory in Alonte, in the Veneto, with other sites in Spain, the United States, Brazil and India. Car makers use its multi-layer gaskets as original equipment, and its competition range is designed and made in Italy.

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, which Peugeot and Citroën do not publish 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: 0209.Z3, 0209.EP, 0209.EQ and 0209.N6.

Important: these two part numbers are reserved for the engines EW10J4, EW10J4S, EW10D and XU10J4R: check your car's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limits, the reinforced gasket takes over: under increased combustion pressure, it keeps its thickness and shape without being crushed.

Turbo, supercharger or raised compression ratio: as power climbs, the head gasket becomes the weak point of the top end. The reinforced gasket rules out the leak, and the head removal it forces, far costlier than the gasket itself.