Tap water contamination
 

I'm in the middle of a very slow coolant and hose-ectomy.
My 2003 4.6 has residue of someone before me using tap water.
The hoses I'm replacing are all caked with white scale.
I'm replacing all items. I'm concerned that the block has the same
white crud inside.
Before I get this X5 running again, I'm wondering how to get the white
film out of everywhere.
Has anyone tried the Prestone coolant flush?

Should I do a flush with the cleaner on the old radiator, or new one?

I'd not worry about it.

One thought: CLR product?

I literally just tried that stuff this weekend on my vert. It has been running tap water for like 4 or 5 years. Explanation: I forgot about it after rebuilding the head and testing for leaks/temps after bleeding. I then sold it shortly after that and bought it back 2 years later. So it had rust and other nastiness in the engine, rad, and hoses. I didn't take any pictures, but it got out A LOT of nastiness. I did somewhere in between the bottles 10 minute flush and their more comprehensive version on the back of the bottle.

I did the flush and then added 50/50 BMW blue and purified water. I'd use the stuff again.

I did a flush with the cheaper Prestone Flush on a VW I had 4 years ago. So much nastiness came out of that thing when I drained it.

I did it because of the goo that had built up everywhere from this old wagon. I actually left it in there for about a week and drove it around before I drained it.

I used the Wurth Radiator Cleaner with very good results.
Had to flush the system a few times with tap water afterwards. Make sure you set the temp setting to max and lowest fan, so you can clean out the heater core as well.

I also used the block drain hole.

Perhaps someone filled it with anti-freeze other than the one specified by BMW. Look like someone might have used phosphate anti-freeze instead of phosphate free anti-freeze.