Rotax MMH-912 Series Maintenance Manual page 130

When replacing the coolant elbow, mark its position, heat the area with a hot air
gun to max. 120 °C (248 °F) and unscrew the fitting. Remove residues of
LOCTITE means and check threads. Apply LOCTITE 648 to the thread on the
cylinder head and to the new coolant fitting and screw the fitting into the cold
cylinder head. Leave cylinder head to harden for approx. 10 minutes at 100 °C
(212 °F).
If there are oil carbon residues on the sealing face with the cylinder, remove them
carefully. Check that the sealing face is level.
In the case of slight wear, valve and valve seat may be seal-lapped, using emery
paste.
Clean cylinder head and individual components with suitable cleaning agents.
See 00-00-00 sec. 10.3.
Check cylinder head sealing surface and if necessary, blue it and the cylinder.
The flat surface of the cylinder and the cylinder head may only be slightly
machined.
◆ NOTE:
If the engine has been "run hot", the hardness of the cylinder head and the
cylinder material must be checked.
See 72-00-00 sec. 5 and the corresponding Maintenance Manual (Line Main-
tenance) for the respective engine type 912 or 914 Series.
Effectivity 912/914 Series
Edition 1 / Rev. 3
BRP-Powertrain
Maintenance Manual
In the event of more serious leakage, cylinder and cylinder head
can be reworked as described in the Overhaul Manual by a
ROTAX authorized overhaul facility.
Fig. 72-59
1
3
00280
2
72-00-00
October 01/2010
page 58