Hitachi ZAXIS 30U-5N Operator's Manual page 249

Procedure:
1. Park the machine following the same procedures as
described on page 7-6 for preparation for inspection and
maintenance.
2. Remove the under cover. Remove radiator cap (1). Open
drain cock (2) on the radiator and the drain cock on the
water jacket to allow the coolant to drain completely.
Remove impurities such as scale at the same time.
3. Close drain cock (2) and the drain cock on the water
jacket. Fill the radiator with soft water containing fewer
impurities or tap water and a radiator cleaner agent.
Run the engine at a speed slightly higher than slow
idle to raise the coolant temperature until the first two
segments come on. Then, run the engine further for
about 10 minutes.
4. Stop the engine and open radiator drain cock (2). Flush
out the cooling system with tap water, until draining
water is clear. This helps remove rust and sediment.
5. Close drain cock (2). Fill the radiator with tap water and
LLC at the specified mixing ratio. When adding coolant,
do so slowly to avoid mixing air bubbles in the system.
Run the engine to sufficiently bleed air from the cooling
system.
6. After adding coolant, operate the engine for several
minutes. Check the coolant level again, and add coolant
if necessary.
MAINTENANCE
2
2
2
7-69
ZX30U-5N, 35U-5N
ZX50U-5N
ZX60USB-5N
MADB-07-033
MADB-07-034
MADC-07-005