General information on inspecting cylinder walls - AH01.00-P-0300-01AMG

Individual blank points, e.g. in middle of cylinder or in area of cylinder head bolts.

Reuse crankcase.

Fig 1: Identifying Pressure Gloss Marks, Smooth Spots On Cylinder Wall

Courtesy of MERCEDES-BENZ USA

Starting from first piston ring, tapering to an end after about 30 mm. Traces of dry friction marks which cannot be felt, caused by oil film being washed off by fuel, e.g. during frequent cold starts associated with short-distance driving. These traces of friction marks which occur principally in area of cylinder head bolts and on pressure side are not a problem provided they are smoothed. The piston rings are not damaged.

Reuse crankcase.

Fig 2: Identifying Visible Mottling, Friction Marks On Cylinder Wall

Courtesy of MERCEDES-BENZ USA

Visible imprints in the upper and lower piston ring reversal range are not a reason for complaint.

Reuse crankcase.

Fig 3: Identifying Ring Shaped Imprints

Courtesy of MERCEDES-BENZ USA

Usually starting from the first piston ring, in the upper area of cylinder, with measurable partial cylinder wear.

Cylinder wall unusable.

Fig 4: Identifying Rotary Bright, Specular, Polished Upper Surfaces Of Cylinder

Courtesy of MERCEDES-BENZ USA

Starting from first and second piston ring, tapering to an end only in bottom part of cylinder. Traces of rubbing as described in item 2, which have advanced to signs of seizure. Piston rings may be damaged.

If damage can be felt, cylinder wall unusable.

Fig 5: Identifying Roughened Mottling, Friction Scoring On Cylinder Wall

Courtesy of MERCEDES-BENZ USA

Caused by contamination, e.g. through reverse pulsation of soot particles out of exhaust.

Reuse crankcase.

Most of cylinder wall perceptibly roughened over the entire length. Material deposits and perceptible scoring marks on cylinder wall and at piston skirt.

Cylinder wall unusable.

Oil varnish is over large areas of cylinder contact surface and indicates, that engine was driven at high temperature level. Reuse crankcase provided no impermissible cylinder distortion is present. Oil varnish above piston ring zone is normal and is not a reason for complaint.