Originally Posted by monkey_wrench
I missed the bit where it said, in the DYI I searched for and found, that I needed to mix a gallon of BMW coolant and a gallon of distilled water.
Perhaps I'm looking at a different DIY.
My question then was, will any coolant do, or do I need special BMW coolant.
From the DIY for water pump replacement on the N52:
"Coolant Refill procedure:
33) Reinstall the blue radiator drain screw.
34) If you didn’t open the bleed screw on the coolant reservoir, open it now (about 4 turns)
35) Slowly fill the system with a premixed 50/50% mix of BMW coolant
and distilled water.
36) Fill the reservoir all the way up to the bottom of the filler neck. The bleed screw will bleed air as it gets trapped in the reservoir. Keep filling until the bleed screw is passing coolant with no bubbles in it. (Keep a paper towel handy to soak up the coolant coming out of the bleed screw).
37) Close the bleed screw.
38) Once the reservoir (system) is full (it will take almost two gallons of antifreeze
) fully close the reservoir cap."
I'm not sure why this is so hard to understand. Just use BMW coolant. It's properly formulated for use in your car and the metals in your engine are selected for BMW formula coolant in the engine. Mixing BMW coolant with distilled water keeps other unwanted minerals present in tap water from forming deposits in the engine. Use of some other coolants with different formulations are not recommended by BMW and may be harmful to the long-term operation of the cooling system. It's not like BMW prices their coolant at twice the price of other brands, so just use it and you know the coorect coolant is in the system. Simple.