Originally Posted by surlynkid
Make sure to use distilled water. It is okay to not know the capacity. Just keep mixing up your own 50/50 blend a little at a time and only add that mix. Keep in mind that there will be residual fluid left in the block after you do these water flushes unless BMW has a plug on the side of the block to remove to get that out. Toyota gives you a block plug to remove. So if you cannot do that, err on the strong side when blend up your coolant and water to end up at 50/50. If you truly knew the capacity, that would help. I would fill and drain 3x with distilled water if I was doing it.
+1 on the distilled water,it's a cheap way to help prevent corrosion.tap water has a lot of minerals which are bad for radiators.i just had a radiator flush and refill done at the dealer,brought in 2 gallons of distilled water for them to use,1 was still about half full,so about 3 gallons was the total fill.
the manual says the coolant is lifetime fill.i plan to change it every 3-4 years.does anyone who is more mechanically savvy than me think it can really be left unchanged for the life of the car?