Doing a coolant drain
 

I want yo do a coolant drain and fill with known mixture of
BMW brand coolant and distiller water.
I know there is a radiator drain plug.
I want to do a COMPLETE drain.
I looked and not found where the block drain plug is.

Is it necessary to drain the block?

Thanks in advance.

Greg

- Do not ever mess with the engine block drain, it is always a pain to deal with.
- I have done complete flush and this is what I do: d/c at the lower rad hose and drain it, then reconnect the hose gently.
- Fill system with distilled water. Run engine around the block.

Repeat the cycles a few times, now you only have distilled water in the engine.

- Now, calculate system capacity, drain the water, fill with pure coolant such that you get around 50-50 mixture.

^^ That's the way I do it, too.

Let it completely warm up during your rinse&repeat cycles, and run the heat on max to flush the heater system. Always fill (and flush) with distilled water and not hose water. You want to avoid depositing minerals inside the engine.

The total capacity is very close to 2 gallons, so after your last drain cycle, add 1 gallon of pure coolant then top off as necessary with distilled water.

^This sounds about right to me as well, I think using the lower rad hose is more about doing the draining quicker. I would always use distilled for flushing as well

:iagree:

Do not pull plugs from the block

Yes distilled water is a must rather than mixing/diluting with tap water.

Ok,
Thank you guys.
Looks like a trip to Wally mart.
Think 4 gallons of distilled water will be enough?

I have lots of blue BMW coolant.
Is this V8 4.4 hard to bleed the air?
The inline 6 can be a little aggravating, luckily
I have a steep driveway.

One reason I don't use the radiator petcock in a 10-year-old car is: the plastic can get brittle and break during removal.

I simple disconnect the lower rad hose, it is safer that way.