Doosan DA40 - Cold engine; Coolant loss; Polluted coolant

Engine
SHOP MANUAL
Ch 1 page 247
Cold engine
Coolant loss
Polluted coolant
Eect Cause Trouble shooting Action
Instrument indi-
cates low tempera-
ture
Defective sensor/instru-
ment
Check that sensor and instrument match each other
(120 and 150 ° C)
Check with a separate instrument
Thermostat jammed in
open position
Check operation of ther-
mostat
Low power output at
low ambient temperature
(large external cooling
surface)
- Fit a thermostat fan
- Fit a smaller fan
- Install a KLAFFO radiator shutter
NOTE: NOT A RADIATOR BLIND
Risk of fan blade breakage
- Reduce the air ow
- Reduce fan/coolant pump gear ratio
Large leakage ow in
thermostat housing
(9- and 11-series marine
engines)
Eect Cause Trouble shooting Action
Defective cylinder head
gasket (external leakage)
External leakage
Coolant pressed out
of radiator on DSI
engines
Turbocharging pressure
enters cooling system
via leaking charge air
element
Test pressure
(air 0.5 bar, liquid 4 bar)
White smoke when
engine hot indicates
water vapour
Crack in cylinder head
(not cracks between
valve seats)
If the fault is hard to trace:
Change all cylinder heads for exchange cylinder
heads.
(Or test pressurize all cylinder heads. Heat the cyl-
inder heads before pressurizing them.)
Cracked cylinder liner
Grey oil = Coolant in oil
Locate the leak by removing the oil sump and pres-
surizing the cooling system while turning the
engine over by hand
Eect Cause Trouble shooting Action
Faulty inhibitor - Clean the cooling sys -
tem and ll it with
coolant as described in
the maintenance
instructions
Overdosed corrosion
inhibitor