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OM 617 – Cleaning the colling system

A. De-oiling

1. Completely drain cooling system.
2. Remove thermostat element and set heater lever to warm.
3. Fill cooling system with a 5 % solution of water and P 3 Standard (made by Henkel) (50 g P3/1 I water
Attention !
On vehicles with alluminium radiator, a neutral cleaner such as P3 Croni (made by Henkel) or Grisiron 7220 (made by Farhwerke Hochst) must be used instead of the heavily alraline cleaner P 3 Standard.
4. Run engine warm at medirlm speed UP tc approx. 80c (176F) and hold at this temperature for about
5 minutes.
5. Stop engine and permit cooling svstem to cool down to approx. 50c (122F).
6. Completely drain solution.
7. lmmediately thereafter, fill cooling svstem twice with fresh water, run warm (approx. 5 minutes) and drain.

B. Decalcification, derusting
Attention !
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 oxal ic acid (sold by the chemical trade), while giving preference to citric acid.
2. Run engine warm at medium speed up to approx. 80c ( 176F)  and hold for approx. 10 minutes at
this temperature.
3. Stop engine and permit to cool down to approx. 50c (122F).
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 decalcification solution and repeat flushing steps.
6. Install thermostat element with new seal.
7. Fill the cooling system with specified coolant specification for service products page 310 to 325).
Note: For decalcification and derusting, commercial products named with the acids nemed above may also be used.
Chromic acid or products containing chromates are prohibited by sewage regulations.


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