Engine cooling,  OM617

Cleaning cooling system



20—015 Cleaning cooling system


Self-made tool


Coupling (1), part No. 002 545 49 28 approx. 1 m cable 1.5 mm2 black (b) + approx. 1 m cable 1.5 mm2 brown (c) -1 cable terminal + 1 cable terminal —
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a = Locating groove


A. De-oiling


1 Completely drain coolant (20-010).


2 Remove coolant thermostat (20-110).


3 On model 116 pull plug of heating water pump (arrow) from supply line. Connect heating water pump to battery by means of self-made tool. Push “DEF” button.
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On model 123 with automatic climate control and on model 126, push “DEF” button (arrow).
On model 123 with and without air conditioning, set
heater lever to max. heating capacity.
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4 Fill cooling system with a 5 % solution of water and a neutral cleaner, or with a mildly alkaline cleaner such as P 3-Croni (supplier: Henkel) or Grisiron7220 (supplier: Farbwerke Hoechst).
On model 116 with heavy-metal radiator, a strongly alkaline cleaner, e.g. P 3-Standard (supplier: Henkel) may be used instead of a mildly alkaline cleaner. Strongly alkaline cleaners may not be used on models 123 and 126 with light alloy radiator.


5 Run engine warm at medium speed up to approx.


80 °C (176 °F) and hold at this temperature for


approx. 5 minutes.


6   Stop engine and permit cooling system to cool down to approx. 50 °C (122 °F).
7   Completely drain solution.
8    Immediately thereafter, fill cooling system twice with fresh water, run warm (approx. 5 minutes) and drain.


B. Decalcification, derusting


Prior to decalcification, be sure to de-oil cooling system, even if there is no visible oiling up.
1 After second flushing job during de-oiling, fill cooling system with a 10 % (100 g/l) solution of water and citric acid, tartaric acid or oxalic acid (sold by the chemical trade) while giving preference to citric acid.


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2 Run engine warm at medium speed up to approx. 80 °C (176 °F) and hold for approx. 10 minutes at this temperature. Proceed according to item 3 section A “De-oiling”.


3   Stop engine and permit to cool down to approx. 50°C(122°F).
4   Completely drain decalcification solution.
5    Flush cooling system at least three times with fresh water while running engine for at least 5 minutes with each flushing charge.
Badly calcified cooling systems may require a repe­tition of the treatment. Always prepare a fresh de-calcification solution and repeat flushing steps.
6    Install coolant thermostat with new sealing ring (20-110).
7   On model 116, connect heating water pump again to electric supply line.
8    Fill cooling system with specified coolant (20-010).
Note: For decalcification and derusting, commercial products made with the acids named above may also be used.
Chromic acid or products containing chromates are prohibited by sewage regulations.


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