560SEL (126.039) V8-5.6L (117.968) (1986)
Engine Block Heater: Service and Repair
Coolant Preheater In Crankcase (Installation Note):
1st Version (A)
2nd Version (B)
NOTE: As of October 1980, the modified screw plug M 38 x 1.5 is installed together with an O-ring.
The chamfer in the crankcase was changed for this reason (2nd version).
When installing a coolant preheater, an O-ring or sealing ring to suit the chamfer in the crankcase should be used.