Coolant Fush Question
 

What Is The Best Way To Completely Flush The System Of The Green Stuff On A 300se W140 Before Refilling With Me/be Clear Antifreeze?

the only way to get all the green stuff out is if you remove your thermostat. Otherwise, fluid will remain in the engine block after you drain the radiator.

Draining from the block is the way to get the most coolant out of your system after you drain the radiator. On a 300 SE it is under the exhaust manifold. (19mm)

Look what I did on my 560SEL 1989:
I filled 66.6% the radiator with white vinegar and the remaining 33.3% with water. The I drove it for two days. After that I empty the whole radiator and flush it in the washing station for million times then I empty the whole radiator using a strong compressed air and finally added 66.6% Mitsubishi coolant and 33.3% distilled water.

It worked perfect.

This is the procedure I would use:

1. Drain fluid, radiator and block
2. Remove the thermostat
3. Reinstall the t-stat housing and upper radiator hose
4. Disconnect upper radiator hose at radiator
5. Flush system with garden hose through upper radiator hose until water runs clear
6. Start car so the engine can flush the water pump
7. Disconnect heater hoses, open heat valve
8. Flush heater core
9. Flush overflow tank
10. Drain as much water as possible from cooling system
11. Siphon water from overflow tank
12. Flush residual tap water from system by replacing it with distilled water
13. Again drain water from system
14. Reinstall thermostat
15. Button everything back up
16. Refill cooling system with specified amount of antifreeze calculated from the system capacity, bring up to level with distilled water
17. Run car, top off coolant with water
18. Keep adding water as required every morning until system is topped off

thanks for all the tips. i first drained the entire system by opening the block drain (what a great feature)then i flushed the system completely until there was only clear water running through system by keeping a flow of water into the resovoir with the car running,heater on,block drain open, & return to resovoir disconnected,until the flow was clear. then i blew out the system with compressed air to get all the water out. then refilled with MB non corrosive coolant & water. ( i didn't use distilled water) the whole process was a little time consuming, but i think it worked fine.