Blue Coolant or Green Coolant

[chadwick405]

Im getting ready to change my cooling system and Im trying to figure out which coolant to run. Right now its got green coolant in it. If I get green again is there any particular brand I should get? The guy at the BMW dealer said the green is ok. I just wanted to see what you guys thought. Also is one 1 gallon jug enough?

[Balthazarr]

Get the BMW specific coolant.
Blue.
Some coolants react badly with aluminum.

[ESMcBlurM3]

Im getting ready to change my cooling system and Im trying to figure out which coolant to run. Right now its got green coolant in it. If I get green again is there any particular brand I should get? The guy at the BMW dealer said the green is ok. I just wanted to see what you guys thought. Also is one 1 gallon jug enough?

Go to the dealer and buy the BMW coolant. You'll need about 2 gallons, and 2 gallons of distilled water to make 50/50. You won't use it all, but you'll need it after the bleeding the system 1,0000 times

[Volf]

I use that prestone 50/50 stuff. Bad idea?

[Rennmeister M3]

I don't think you'll have a significant issue using the green stuff as it's the coolant used in most Japanese aluminum engines for decades. The blue is designed for the specific engine, so it's probably worth the few extra bucks.

[chadwick405]

What about that phosphate free zerex?

[M3BimmerBilly]

Zerex G-05 is the best non-BMW blue alternative. Both come from the same manufacturer and the composition is more or less identical

[chadwick405]

Yah I feel that I might use the zerex just because whats in there is already green, that way I could stick with the same color.

[ESMcBlurM3]

Yah I feel that I might use the zerex just because whats in there is already green, that way I could stick with the same color.
:confused

You are going to be flushing the system when you do your overhaul.

[chadwick405]

Is the zerex G-05 green?

[stupenal]

Is the zerex G-05 green?

No. Mine was clear. Looked like syrup/cooking oil.

[chadwick405]

I think im just going to pick up 2 gallons of blue and 2 gallons of distilled and change it all out.

[Ron97M3]

You could use 1 quart of redline water wetter $7
1 gallon of BMW blue for $20
and 1.25 gallons of distilled water.
That is what I did.

Water wetter actually cools better with less coolant in the mix so 40% or 45% coolant would be better, unless you want -40 degree freezing protection instead of maybe -20?

So drain, flush, drain and then add wetter and 1 gallon of coolant with
the balance 0.75? gallon of distilled water. Then add water till bled for days
as needed.

Getting at the block drain bolt is an issue and bleeding can take 5 sessions. If your heater doesn't blow HOT air as the temp rises that means you still have a lot of air in the system. To avoid cracking the block/head let the car cool down to near the bottom third before opening the bleed screw just to be safe. It took me maybe another half gallon of ater to top off in bleeding process before I quit getting "coolant low" messages tank held at level once the car cooled.

[Balthazarr]

I guess I'm lucky in bleeding my car.
4 coolant changes and
never had the issues most people seem to have with air in the system.

[Ron97M3]

First time I had no problem but the second time here I had quite a bit of air in the system and I had to play bleed and top off maybe 4 or 5 times.

This time I had replaced the hose between the expansion tank and the block-head so I assume that got air into the heater core and such perhaps.

[chadwick405]

Ok sounds good, my friends shop is going to do it, Im a college student so i have no tools with me they are all at home, or time to do it, but ill give him the bleeding tips.

[Ron97M3]

After slowly filling the car back up with fluid it will take about 2 gallons total
I bet.

Then you warm the car up with the heater on. My car didn't threaten to over heat until I drove it around the block. If you can't get truly hot air out of the heater when the car is idling it has LOTS of air in the system and will likely overheat if driven. Of course you NEVER put cold water in a really hot engine or things can crack $$$$$$$$.

Once you get hot heater air you are close but not perfect. Likely you will still see the coolant low message once you drive the car to full heat and then turn it off. At medium or lower temp guage heat now you can open the bleed screw and let air escape but you need to let the car cool for an hour or maybe several to see the lowest water level in the expansion tank perhaps. When tightening the bleeder screw don't tigtenned it too much as it can strip. In fact the screw is $2 at rmeuropean.com and I am ordering another soon.

To top off you just need distilled water. I played with this like 5 times over 5 trips in several days adding maybe a cup or two of water each time before the level stayed full. Total fluid about 2.5 to 2.75 gallons.