Hitachi EX1900-5, Operator'S Manual

Page: 211 / 281

MAINTENANCE
7-79
Change Coolant
--- twice a year (in spring and autumn)
NOTE: Before leaving the Hitachi Factory, the cooling
system is filled with a mixture of water and
Genuine Hitachi Long-Life Coolant.
As long as Genuine Hitachi Long-Life Coolant is
used, the service intervals between changing
the coolant is once every two years, or every
4000 hours, whichever comes first.
CAUTION: Do not loosen the radiator cap until
the engine is cool. Loosen the radiator cap slowly
to the stop. Release all pressure before removing
the radiator cap.
1. Park the machine on a solid and level surface. Lower
the bucket to the ground. Stop the engine.
2. Remove plugs (3) and open drain cocks (2). Slowly
open cock (2) to bleed air pressure. After the air pres-
sure is released, open engine drain plug (4).
3. Close drain cock (2) and install plug (4). Open bleed
air cocks (6). Remove radiator cap(1). Fill the radiator
with soft water which contains less impurities or tap
water and a radiator cleaner agent. Start the engine
and run at a speed slightly higher than slow idle; when
the needle of the temperature gauge reaches the
white zone, run the engine for about ten more min-
utes.
4. Stop the engine and open radiator drain cock (2) and
remove plugs (4). Flush out the cooling system with
soft water or tap water, until the draining water is clear.
This helps remove rust and sediment.
5. Close radiator drain cocks (2) and (5) install plugs (3)
and (4). Fill the radiator with soft water or tap water. At
that time, mix the antifreeze (or LLC) or anti-rust
agent. Slowly add coolant to avoid mixing air bubbles
in the coolant system. Close bleed air cocks (6).
6. Start the engine. Sufficiently bleed air from the cooling
system.
7. After adding coolant, operate the engine for several
minutes. Check the coolant level again.
Add coolant if necessary.
M18C-01-009
M18C-07-037
M18C-07-067
M18C-07-070
2
5
1
3
4
6