MTU 12 V 4000 M23F Operating Instructions Manual page 26

Plugs and sensors (a)
Screw-in plugs (4) are sealed toward the outside either with a copper sealing ring (1), according to DIN,
or an O-ring (ISO).
In case of a loose thread or a defective sealing ring (1), the liquid first has to pass the thread.
The pressure is so greatly reduced by this and the faulty sealing ring (1) that any leakage is not under
pressure.
Plug-in pipe union (b)
The sleeve (3) covers the joint to prevent lateral spray.
Only leak-off along the line is possible, the pressure is decreases significantly if an O-ring (2) defect
occurs.
The union is confirmed as being SOLAS-compliant by DNV and GL.
26 | Product Summary | MS150068/01E 2014-01