Mitsubushi ST2R-Y1IPTA. — Changing Coolant

For the Mitsubushi ST2R-Y1IPTA..

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Procedure

1. Lower the coolant temperature to 70 to 80°C (158 to 176°F)
2. Open the radiator cap
3. Place coolant receiving cans under the drain cocks on the engine and water pump
4. Open the drain cocks to drain coolant
5. Close the drain cocks or plug
6. Pour a cleaning solution (non-corrosive solution to rubber and metals) in the cooling system
7. Operate the engine at 800 to 900 min-1 for about 15 minutes, then drain the cleaning solution
8. Close the drain cocks or plugs
9. Pour fresh water and operate the engine at 800 to 900 min-1 for about 10 minutes
10. Continue flushing the cooling system until the draining water is clear
11. Make sure the drain cocks on the engine and water pumps are closed tightly
12. Remove the expansion tank cap and pour undiluted LLC
13. Pour water (soft water with minimal impurities, such as tap water) slowly to the full level
14. Check the expansion tank and other parts for coolant leakage
15. If coolant leakage is found, repair it
16. When coolant reaches the full level, close the expansion tank cap securely
17. Crank the engine for about 10 seconds or less using the starters (with fuel supply shut off)
18. Wait for about 1 minute, then repeat the cranking operation several times to remove air from the water pump
19. Check the coolant level in the expansion tank

Source: manual:Mitsubishi S12R-Y1PTA Manual.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.