Cleaning the cooling system.

[koan]

As requested from the M100 engine book.

20-015 Cleaning the cooling system

A. De-oiling

1 Completely drain coolant.

2. Remove coolant thermostat and set heater levers to warm.

3 Fill cooling system with a 5% solution of water and a neutral cleaning agent or with a mild alcaline cleaner such as P 3-Croni (supplier: Henkel) or Girisiron 7220 (supplier: Farbwerke Hoechst).

4 Run engine warm at medium speed up to approx. 80C (176F) and hold at this temperature for approx. 5 minutes.

5 Stop engine and let cooling system cool down to approx. 50C (122F).

6 Completely drain solution.

7 Immediately thereafter, fill cooling system twice with fresh water, let system run warm (approx. 5 minutes) and drain.

B. De-calcification, de-rusting

Attention!
Prior to de-calcification, be sure to de-oil the cooling system, even if there is no visible oiling up.

1 After second flushing job during de-oiling, fill cooling system with a 10 % solution of water and citric acid, tartaric acid or oxalic acid (sold by 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 cooling down to approx 50C (122F).

4 Completely drain de-calcification solution.

5 Flush cooling system at least 3 times with fresh water, while running engine for at least 5 minutes with each flushing change.

Badly calcified cooling system may require repetition of treatment. Always prepare a fresh de-calcification solution and repeat flushing steps.

6 Install coolant thermostat with new sealing ring.

7 Fill cooling system with specified coolant (specifications for service products sheet 310 to 325).

Note: For de-calcification and de-rusting, commercial products made with the acid named above may also be used.

Chromic acid or products containing chrome are prohibited by sewage regulations.



koan

[Sev]

for step 4a, i'd jack the car up and let it idle longer, to 'burp' the system (i.e. remove all lingering air bubbles).