Flushing Coolant Question

[gverelli]

I have a question, after flushing the rad, and the block how to do I go about completely cleaning out the old green coolant? Im doing my waterpump/timing belt and was going to use refill coolant with BMW blue coolant, I just don't want it mixing with whatever green coolant is left, How do I go about really cleaning out the old green coolant from the block and rad? The rad Im presuming will be completely empty after I take it out and shake it a bit, but for the block I know there will be sitting puddles of green in there...?

Thanks in advance

[jlevie]

Drain the radiator and block. Fill the system with plain water and properly bleed the cooling system (procedure below). Then drain the system again and refill with coolant.

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.

[gverelli]

^^ Perfect thanks!

[!kid]

would it be better to use distilled water to flush out the block and not tap water? some will be left inside the block even after all the green stuff is out.

[gverelli]

^^ Good question actually, better to use distilled or regular to flush out the old?

[!kid]

if it where me i would use distilled.

[jlevie]

Plain water is fine for flushing out the block. But it is best to mix anti-freeze with distilled water.