Okay, I am going to change out the coolant in my 300e. It is the same coolant that has been in it since my dad bought it about 3 years ago. It is a funny brownish green color. I don't know what kind it is. I want to get as much of it out as possible, to prevent possible reactions with the new coolant (Zerex G-05). I know where the drain is on the bottom of the passenger side of the radiator. I don't know exactly where the drain is on the block.
Can anyone tell me where to look for this drain?
Are these the only two drains for coolant?
To flush with regular water, should I just close the drains, fill up through the resevoir tank, run for a bit, then drain again?
Is that all there is to it?
Will a simple water flush be sufficient to expel the old coolant?
Any other tips or quirks I should know before doing this?

Thanks for your time.

p.s. Did a search already, and all the threads seem to break down to an argument over which coolant is best, with little info on actually performing a fluid change. If someone can provide a link to a thread which has already answered my questions, it would be just as good. Thanks.

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headrivenoise... listen.

Block drain is on the rear of the block, down low, more or less behind the exhaust manifold on the passenger side. Very nicely, there is a hose nipple on it so you can direct the used coolant into a bucket or empty antifreeze container instead of all over the floor like on the older engines.

Fill completely with water and drain a couple times will be sufficient if you are just changing coolant. If you do the citric acid flush, you need to circulate both the flush and the rinse with an open thermostat, else you will have corrosion problems from residual citric acid.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I just replaced the radiator on my 88 300ce, and according to the Haynes manual ( in the regular maintenance section), engine flushing is accomplished first by draining the engine at the block & then disconnnecting the upper & lower radiator hoses & removing the thermostat, & then inserting water from a garden hose into the upper hose until it comes out the lower radiator hose & runs clear. I'm not sure what this actually means, so my questions are: First, do I run the engine after filling the block, and second, should I run the engine until clear water comes out the lower radiator hose & until all the water is out. BTW, the manual says heater should be running and set at full heat. Thanks

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)