Coolant flushing

[Any1else]

Changed my CCV system yesterday and while the manifold was off I changed the two coolant pipes on the block meaning that I had to drain some of the coolant. Turned out it was brown rather than blue so now I need to flush the coolant and replace it and that leads me to a few questions. A bit of Googling seems to offer various answers and I wonder if I can get some clarity here?

1. Can I use Comma G48 or is the consensus that the BMW oem should be used?
2. Distilled water seems to be the go-to but it isn’t easy to come by in the UK so what does everyone else use along with the antifreeze? Some sources say that the tap water in the UK is fine to use due to the higher quality (I am in Scotland and don’t have hard water or need to descale kettles etc)
3. What is the capacity of the E85 M54 coolant system. Info varies between 4.5 and 10.7 litres.
4. Any recommendations on the flushing process and whether I need to remove both drain plugs (block and rad). Should I be looking at using a flushing additive?

[bigwinn]

Hi mate

Anything is better than the sludge currently in it! I’ve used comma and bmw fluid and they don’t seem to make much difference

I do use distilled water- Halfords and GSF sell it ( the water here is so hard it’s one lump or two)

I usually buy 5L coolant and top up with distilled water (approx additional 1L)

I’d deffo take the engine block plug out to make sure it’s all drained

[Any1else]

Cheers bigwinn, I will deffo be changing it. Been having a look and think I will go for the Comma G48 that is already mixed. Guess I can just flush out with tap water and fill with the G48 when it runs clear. Will have a search for the block drain and order one cos I read they are one time use.