Cleaning Cooling System - Man D 2842 LE 620 Repair Manual

Cleaning inside of cooling system
Tests have shown that in many cases the poor condition of the coolant and / or the cooling system ac-
counts for damage to the coolant pump seal. The poor condition of the cooling system is normally due to
the use of unsuitable or no antifreeze or corrosion inhibitor or to defective caps for filler necks and service
valves which are not punctually replaced.
If the coolant pump of an engine develops leaks twice in short succession or the coolant is heavily contami-
nated (cloudy, brown, mechanically contaminated, grey or black signs of leakage on the coolant pump
housing, after the defect on the oil cooler), clean the cooling system prior to removing the faulty coolant
pump as follows:
a) Drain coolant
b) Open the thermostats positively (use bypass inserts) so that the entire cooling circuit is flushed immedi-
ately during the cleaning operation
c) Fill coolant circuit with a mixture of hot water (min. 50°C) and Henkel P 3 neutrasel 5265 detergent
(1.5% by volume) (−5266, −5225, Kluthe Hakopur 316), refer to Publication "Fuels, Lubricants ..."
d) Warm up the engine under load. After a temperature of 60°C is reached, run the engine for a further 15
minutes
e) Drain cleaning fluid
f) Repeat steps c) and d)
g) Flush the cooling circuit; to this effect
h) Open the drain valve slightly
i) Fill the cooling circuit with hot water
k) Run the engine at idle for 30 minutes. At the same time, continuously replenish the water emerging
through the drain valve by adding fresh water at the filler neck
l) Drain off cleaning fluid and close the drain valve
Only now should the coolant pump be repaired. On completion of repairs, fill the cooling system with cool-
ant, refer to publication "Fuels, Lubricants ...".
Note:
Only sediments and suspended particles can be removed by this cleaning method. If rust and lime
deposits are detected, proceed following the instructions set out in the section below:

Cleaning cooling system

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