Mercedes Benz reports that all passenger cars and light trucks equipped with the M272/273 engine (up to June 2998 production) may experience engine oil seepage.

The location could be the round expansion plugs on the rear of the cylinder heads. As of June 2008 production, improved plugs were phased into production.

If these plugs are leaking, remove the existing plugs and replace with P/N A000 998 55 90 (two small expansion plugs) and A000 998 56 90 (one large expansion plug on engines without vacuum pump). 

Large plug (left) and small plug on rear of cylinder head.

Large plug (left) and small plug on rear of cylinder head.

The initial supply of plugs will feature the old part number molded into the plug along with a white dot.

The early supply of replacement plugs feature a small white dot.

The early supply of replacement plugs feature a small white dot.

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