Determine loss of pressure at cylinder - AH01.00-P-1300-02AL

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ENGINE 640.941 in MODEL 169.0/3, 245.208

ENGINE 640.942 in MODEL 169.0/3

ENGINE 640.940 in MODEL 169.0/3, 245.207

If an increased pressure loss was found with the cylinder leakage tester, inspect engine by listening at cylinder head gasket, air intake area, exhaust, oil filler opening, coolant filler opening, coolant connections and glow plug hole of the adjacent cylinder or cylinders.

Possible causes of pressure loss given the following symptoms are:

Air escaping via glow plug hole or adjacent cylinder, in coolant expansion reservoir or coolant connections:
Pressure loss at cylinder head gasket
Air escaping via air intake section:
Pressure loss at intake valve(s).
Air escaping via exhaust:
Pressure loss at exhaust valve(s).
Air escaping via oil filler opening:
Pressure loss via pistons and piston rings.

Spraying engine oil into the cylinder can limit the pressure loss from that cylinder. Engine oil temporarily seals the gap between the piston and cylinder.

If a reduced pressure loss then occurs temporarily, the cause is highly likely to be the piston, the piston rings or the cylinder barrel of the cylinder in question.

Troubleshooting the cause can be hampered by the position of the piston ring end gaps. If it is suspected that pressure loss is being caused by the piston ring end gaps being directly over each other, reassemble the engine and repeat the test after running the engine briefly.