[Welcome to NBA Jam]

I just flushed my cooling system with distilled water 3x.

Initial drain: 1 Gal, radiator only
First distilled drain: 0.75 gal, radiator only
Second distilled drain: 0.75 gal, radiator only
Third distilled drain: 1.25 gal, radiator + thermostat

This is only about half of the cooling system capacity. I want to maintain a 50/50 ratio of coolant to distilled water when I do my final fill.

Is there any way to get the rest of the distilled water out of the system? Would running the water pump without coolant to try and force more out be a bad idea?

For reference, the N55 when dry is 9.3L for manual transmissions, and I only drained about 4.7L.

What would you recommend for refilling?

[mweisdorfer]

Originally Posted by Welcome to NBA Jam

I just flushed my cooling system with distilled water 3x.

Initial drain: 1 Gal, radiator only
First distilled drain: 0.75 gal, radiator only
Second distilled drain: 0.75 gal, radiator only
Third distilled drain: 1.25 gal, radiator + thermostat

This is only about half of the cooling system capacity. I want to maintain a 50/50 ratio of coolant to distilled water when I do my final fill.

Is there any way to get the rest of the distilled water out of the system? Would running the water pump without coolant to try and force more out be a bad idea?

For reference, the N55 when dry is 8.2L for manual transmissions, and I only drained about 4.7L.

What would you recommend for refilling?

Do you have the heat going when you are moving the coolant/distilled water.

Anyway of detaching a lower radiator hose and running the engine a little to force the water pump to sort of pump the coolant & water out into a bucket ?

https://www.pelicanparts.com/BMW/tec...ng_System.htm#

Personally, I use Amsoil Coolant w/ a coolant booster

[Welcome to NBA Jam]

Originally Posted by mweisdorfer

Do you have the heat going when you are moving the coolant/distilled water.

Anyway of detaching a lower radiator hose and running the engine a little to force the water pump to sort of pump the coolant & water out into a bucket ?

https://www.pelicanparts.com/BMW/tec...ng_System.htm#

Personally, I use Amsoil Coolant

That was the guide I followed as well. I could run the pump in bleed mode to move coolant without the engine running, but I don't know if running the electric water pump dry will damage it.

[mweisdorfer]

Originally Posted by Welcome to NBA Jam

That was the guide I followed as well. I could run the pump in bleed mode to move coolant without the engine running, but I don't know if running the electric water pump dry will damage it.

I looked in the Bentley Repair Manual and it did not address it. I know Liqui Moly makes a radiator flush.

[whyzee125]

I've always used one gal. of BMW coolant and then I top off with distilled water. It may not be as exact as I thought but that's what my dealer recommended and based on my receipts it looks like that's what my Indy did too. If you want to be more exact, I get that, but I think this is a plenty safe way to go.

[PichaDis11]

I've only read that the pump should be stored with coolant to prevent impeller shaft from seizing. But IMO, i would not operate it without some coolant/liquid in the system.

This maybe what you are running from and will be a PITA but best to get that "U" shaped hose that connects the water pump to the engine. Should be able drain more from the engine. Just gotta be careful to not drink coolant when the hose gets off.

[mweisdorfer]

Originally Posted by Welcome to NBA Jam

That was the guide I followed as well. I could run the pump in bleed mode to move coolant without the engine running, but I don't know if running the electric water pump dry will damage it.

https://www.e90post.com/forums/showthread.php?t=551742

Check this one out...

[Welcome to NBA Jam]

Originally Posted by whyzee125

I've always used one gal. of BMW coolant and then I top off with distilled water. It may not be as exact as I thought but that's what my dealer recommended and based on my receipts it looks like that's what my Indy did too. If you want to be more exact, I get that, but I think this is a plenty safe way to go.

Awesome, thank you. That is what I am doing. I've got a whole other bottle left, so I'll test out the specific gravity of it some time later to be sure it has adequate freezing protection. Worst case, I just drain and refill again.

Or I'm overthinking it. The TIS just makes it seem extremely crucial.