N55 coolant replacement
 

My N55 has pink coolant in it, thats not ok I should be blue.

I have a new waterpump and thermostat and BMW blue coolant.

The question is how do i get all the pink coolant out? Because mixing the coolant is not a very good idee.

Did a search but all i can find is how I get just half the coolant out.

If it has a block drain, removing that will greatly aid in getting out more of the old coolant. Otherwise, removing the lower connection of the lower radiator hose will also usually release more coolant. Other than that, you can then leave the drain open at the bottom and continue adding water (garden hose is convenient) to flush out the old coolant. You might want to do a couple fill/bleed/drain cycles also. You should have it all but eliminated from the cooling system by this time. You can leave the tap water in there, or if anal, flush it out with deionized water. Regardless, you're going to have a significant volume of water in your system. Hence, begin your final fill by adding the full amount of undiluted BMW coolant to your system. In other words, if your system holds 10.6 qts for example, you would add 5.3 qts. of undiluted coolant. From there, you can finish the final fill/bleed process using more water, so you'll end up with your perfect 50% mixture.

AM.

The capacity of the E70 N55 is 10.9l or 2.87 gallons.
If you are that peculiar you can flush it with distilled water then drain (now you have distilled water in your system) and add 1.44 gallons of undiluted coolant then fill the rest with distilled water.

COOLANT, COOLING SYSTEM TEST N55 > 17 00 COOLANT, COOLING SYSTEM
TEST
COOLANT, COOLING SYSTEM TEST SPECIFICATION
Coolant volume with integrated air conditioner AT Liters 10.9
Top-up quantity of coolant in the event of repair with disconnected coolant hoses.
Observe the mixture ratio and filling level! See RADIATOR -- OPERATING FLUIDS .
Liters 2.0
Test pressure for cooling system (excess pressure) bar 1,5

Agree w mid. Id skip too much effort at opening everything up to DRAIN it. Get out as much as you can, then flush w clean water. Then a final DI water flush.


Whatever slight impurities remain SHOULD be handled by the stabilizers in the fresh fill. I WOULD use DI for the final fill water portion