My coolant is green, my new bmw coolant is blue...

[JubJub]

I read on a Pelican Parts how to that if you put in coolant and didn't use distilled water that it ran the change of doing something to the sulfides (or something like that) that effectively made your coolant turn into a gel like substance and green.

Now I don't buy it turning whatever was in there green, as I am sure the PO probably put green coolant in, but I do now have the problem of having blue coolant on hand when green was used before.

I was also told not to mix colors. Does anyone know if I have to flush out my system more thoroughly and how to do it?

Also read that my car (325e) takes about 11 liters (11.6 quarts) (which should be a 50/50 mixture of distilled water and coolant). Is this accurate? If so 1 gallon that I bought (3.8 liters) isn't enough to top off the system is it?

[Bimmerman325i]

green and blue can mix without problem. Alternatively, keep flushing until there's no green left.

[nrubenstein]

Flush it thoroughly, but mixing shouldn't be a problem.

[jlevie]

It is easy enough to clean out the green coolant. Drain the system (from the radiator and block). Fill with plain water, set the heat for max temperate and run through the bleed procedure. Then repeat at least once more. That will get all of the old coolant out.

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500rpm for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.