Radiator flush

[Mittelklasse]

Alternatively, this is how I did:

1. Engine off and cold, drain the expansion reservoir.
Then, flush it several times with tap water till the water becomes clear.
Refill the reservoir with tap water.

2. Unplug radiator inlet (top) hose. Place a bucket beneath to catch the toxic coolant.

3. Run the engine. When the thermostat opens and coolant flows out of the block,
top up the reservoir with tap water. Let it flush the block until the outlet water is clear.
(You guys with heater might need to turn it on too, for a complete flush)

4. Stop the engine. Drain the reservoir again. Fill it with your coolant of choice and (preferably)
distilled water, up beyond the FULL mark. Don't plug the radiator inlet hose in yet.

5. Run the engine again. The coolant will push the previous tap water out of the block.
Top up the reservoir when the coolant level falls below the middle point.
(To prevent air from entering the system)
Keep an eye out on the color of the outlet water, and be ready to plug the hose back in.

6. Let it circulate good. 'Massage' the hose to push out any residual air bubbles.
Top up the reservoir if necessary.