Hitachi Zaxis 345USLC-6N Operator's Manual page 328

--- Visual Inspection
The coolant level must be between the FULL (3) and LOW (4)
marks on expansion tank (2).
If the coolant level is below the LOW (4) mark, remove cap (1)
from expansion tank (2) and refill coolant.
d
CAUTION: Do not remove cap (1) until the coolant
temperature in the radiator becomes cool. Hot steam
may spout out, possibly causing severe burns. After
the coolant temperature has lowered, slowly loosen
cap (1) to release the air pressure inside before
removing cap (1).
If expansion tank (2) is empty, add coolant to the radiator and
then to expansion tank (2).
MAINTENANCE
1
7-66
3
4
2
MDD5-07-006
MDAK-07-048