Man D 2840 LE 301 Repair Manual page 53

Removing lime deposits in cooling system
Proceed as follows:
D Drain coolant
D Fill the system with undiluted original pickling fluid (lithsolvent acid or engine pickling fluid RB-06). Keep
the engine running for approx. 8 hours with this fluid in the system (also in normal operation)
D Drain the pickling fluid and flush the system thoroughly with tap water
D If necessary, refill the system with fresh pickling fluid and pickle the system for a further 8 hours
D Drain the pickling fluid, fill the system with tap water, and run the engine at idle for 5 minutes to flush out
all fluid; then drain the water
D Fill the system with soda solution (1%). Drain the soda solution after running the engine at idle for 5 min-
utes, and flush with tap water until the discharging water runs clear
D Fill cooling circuit with a mixture of potable tap water and anti−freeze with at least 40% by volume, refer
to Publication "Fuels, Lubricants ..."
Filler caps and service valves of cooling system
The rubber seals on the filler caps and service valves (negative pressure and positive pressure valves) of
the cooling system are subject to natural ageing.
To prevent leakages in the cooling system together with the associated loss of pressure and its conse-
quences through to serious engine damage, replace the filler caps and service valves at the same time as
changing the coolant (every two years at the latest).
Waste water treatment
Drained and spent cleaning and pickling fluid should be brought up to a pH value of 7.5 to 8.5 with the aid
of caustic soda. Once the precipitation has settled to the bottom of the container, the clear fluid above can
be tipped into the sewer system. To be sure, it is advisable to consult the local authorities for more informa-
tion on waste water rules and restrictions. The sludge at the bottom must be taken to a special waste
dump.
Cleaning cooling system
51