Cooling system flush and fill experience.

[g300d]

So after finally flushing most all of the oil due to a failed trans oil cooler out of my cooling system, I did a complete system flush and fill with BMW coolant and distilled water today.

It was fairly straightforward. Removing both lower engine covers allowed me to remove the radiator drain and engine block drain.

Most DIYs seem to mention the block drain is hard to reach and required a few extensions...I was able to get it loose with a 12pt box wrench and unscrew it by hand.

Now with both drains open I thought I got all the old coolant out. But to make sure I stuck a air hose in the coolant tank opening and let 'er rip. I was able to push a considerable amount of water out. I wanted to get it all out because it was filled with tap water at the time.

Of course I didnt have the BMW coolant on hand at the time so I closed all the drains, filled her up with distilled water, and drove to the dealer to get some coolant.

Back at the garage, I drained the radiator only. I got around a gallon of water which coincidentally is about the same amount of coolant I need to add to get a 50/50 mix (cooling system is 8.4 liters capacity if the source I read was right). So I just poured the gallon of coolant into the radiator and it pretty much topped the system up.

So the only thing I have to add to the DIYs I read is to stick an air hose in the coolant fill opening to get ALL the old coolant out, becuse just opening the drains will not get it all out.