Green/blue coolant (I'm color blind)

[jonathan13]

Okay, so as the title says I'm color blind, and that's a key part of this post.

I got in my M3 the other day to leave work, and got a low coolant warning, so I went to the parts store and grabbed some blue "European" coolant. I get home and discover it appears my expansion tank is leaking at the seam as they do (no big deal, I get that ordered). The coolant was so low in that expansion tank though that I couldn't see any of the coolant, and as stated I'm color blind. So I went ahead and topped it off with the blue stuff I purchased.

Today I go to check the level again to make sure I'm good while I wait on the expansion tank to arrive, and I'll be da**ed if the coolant isn't green. I freak out not knowing BMW had switched to green coolant, and start wondering how blocked my coolant passages are from running the wrong coolant since I bought the car (about a year ago). Well after looking online I see that BMW switched to the green stuff, and the panic subsides.

Now my question is do I need to do a complete flush and put all new green coolant in since I've now mixed the two thanks to being color blind? Any insight on this would be greatly appreciated.

Side note- yes I double checked the expansion tank for the intercooler, and it appears to be good, albeit green, but good, so I believe my main expansion tank failure diagnosis is solid at the moment.

[FaRKle!]

The new BMW green coolant is backwards compatible with BMW's older blue coolant cars. That said, I don't know what the "auto parts store" blue coolant has in it compared to BMW's blue coolant...

[hC1001]

Originally Posted by jonathan13

Okay, so as the title says I'm color blind, and that's a key part of this post.

I got in my M3 the other day to leave work, and got a low coolant warning, so I went to the parts store and grabbed some blue "European" coolant. I get home and discover it appears my expansion tank is leaking at the seam as they do (no big deal, I get that ordered). The coolant was so low in that expansion tank though that I couldn't see any of the coolant, and as stated I'm color blind. So I went ahead and topped it off with the blue stuff I purchased.

Today I go to check the level again to make sure I'm good while I wait on the expansion tank to arrive, and I'll be da**ed if the coolant isn't green. I freak out not knowing BMW had switched to green coolant, and start wondering how blocked my coolant passages are from running the wrong coolant since I bought the car (about a year ago). Well after looking online I see that BMW switched to the green stuff, and the panic subsides.

Now my question is do I need to do a complete flush and put all new green coolant in since I've now mixed the two thanks to being color blind? Any insight on this would be greatly appreciated.

Side note- yes I double checked the expansion tank for the intercooler, and it appears to be good, albeit green, but good, so I believe my main expansion tank failure diagnosis is solid at the moment.

Its not gonna clog and have catastrophic failure. As Farkle said, its backwards compatible. That said, on the next coolant flush, you should flush and only use one type. You can pour a gallon of distilled water while the hose is disconnected at the bottom to try and get most of the old coolant out.

They say to use green for cars made 2018+. Im sticking to blue since it doesnt require to flush every 2 years like the green one. I also dont think theres any difference between F80/F82 2015 and 2020 model cars in terms of the coolant system. They were designed with blue coolant originally.

Probably a different story for new model cars introduced 2018+.

[jonathan13]

Appreciate y'all's responses. That was the big thing I was worried about- gunk and corrosion.


Since mine has the green stuff, and I'm not yet due for a flush on the intercooler system, I think I'm gonna go back with the green this go around for the main system to avoid having blue in one, and green in the other. Next year when it's warm outside, maybe I'll switch both systems back to the blue since it doesn't require a flush every two years.


Like was suggestion, I'll try to run some distilled water through it as much as possible when I replace the expansion tank before filling it back up with green. Heck, since I'm color blind, by the time I'm done, I probably won't be able to tell if it's green or blue anyway, so I'll just tell myself I did a fantastic job at flushing. 😂

[Dabeamerking]

HT12>