Coolant is green and need to top it off?

[HeatGun]

Hi all,

I realized that my coolant level is slightly low, I had a gallon of blue BMW coolant sitting in my garage but I am not sure if I can mix the blue coolant with green ones?
I just learned that BMW does not use the blue coolant anymore, it is green only but I already have the blue coolant which was made for BMW.
Is it safe to add blue on top of green or do I need to go to the dealer and buy a green one instead?

[AlmondJayRoM3]

Originally Posted by HeatGun

Hi all,

I realized that my coolant level is slightly low, I had a gallon of blue BMW coolant sitting in my garage but I am not sure if I can mix the blue coolant with green ones?
I just learned that BMW does not use the blue coolant anymore, it is green only but I already have the blue coolant which was made for BMW.
Is it safe to add blue on top of green or do I need to go to the dealer and buy a green one instead?

It isn’t recommended. Looks like they’re compatible and green can be mixed in with cars filled with blue but not the other way around. Pasted from getbmwparts:

BMW HT-12 can be used in any vehicle that currently contains G48 coolant (blue), but G48 should not continue to be used in vehicles that were originally filled with HT-12. (see compatibility image) This HT-12 Antifreeze/Coolant is exclusively formulated and produced for BMW to protect your engine year-round when used as directed. It fulfills the very high standards and requirements set by BMW to help protect the engine against freezing, boil over, corrosion, and excessive silicate gel precipitation. This ethylene glycol-based antifreeze contains no nitrites or phosphate, greatly reducing the possibility of harmful deposit formation. BMW antifreeze provides protection for metals such as cast iron, steel and aluminum.

[JamesGames]

Originally Posted by HeatGun

Hi all,

I realized that my coolant level is slightly low, I had a gallon of blue BMW coolant sitting in my garage but I am not sure if I can mix the blue coolant with green ones?
I just learned that BMW does not use the blue coolant anymore, it is green only but I already have the blue coolant which was made for BMW.
Is it safe to add blue on top of green or do I need to go to the dealer and buy a green one instead?

You're in california man. It won't ever freeze up - if you are just slightly low top it off with distilled water.

The coolant is contained in a sealed system, however. If you are low and need to keep replacing, there is probably a leak somewhere.

[BzsBimmer]

Check around your expansion tank seam. If there’s residue, it’s probably leaking.

I did a DIY a while ago. If done right, can swap it out easily without needing much coolant to top off.

[HeatGun]

I just bought this M4 and not sure if it’s loosing coolant or not. It’s little less than full. I just dropped it off at an Indy shop for an oil change. The tech will fill up coolant. I’ll monitor for leaks thank you.
Note: Indy charges $92 for an oil change including top off for coolant

[Slo_F80_Mike]

Originally Posted by HeatGun

I just bought this M4 and not sure if it’s loosing coolant or not. It’s little less than full. I just dropped it off at an Indy shop for an oil change. The tech will fill up coolant. I’ll monitor for leaks thank you.
Note: Indy charges $92 for an oil change including top off for coolant

Originally Posted by HeatGun

I just bought this M4 and not sure if it's loosing coolant or not. It's little less than full. I just dropped it off at an Indy shop for an oil change. The tech will fill up coolant. I'll monitor for leaks thank you.
Note: Indy charges $92 for an oil change including top off for coolant

You might wanna check your charge cooler if that's the tank which is low (smaller tank in the back by firewall). They have a tendency to leak the coolant leaks all into the intake ports and cylinders. If you're keeping the car for a while I'd recommend just upgrading the charge cooler.

[b74heavy]

Originally Posted by HeatGun

Hi all,

I realized that my coolant level is slightly low, I had a gallon of blue BMW coolant sitting in my garage but I am not sure if I can mix the blue coolant with green ones?
I just learned that BMW does not use the blue coolant anymore, it is green only but I already have the blue coolant which was made for BMW.
Is it safe to add blue on top of green or do I need to go to the dealer and buy a green one instead?

My manual for my M340i says not to mix coolants of different colors. I just ran into the same thing. My 2023 M340i needed a top-off today before I went on a trip. It has 6200 mi on it so far. I also had a quart of blue collant from my old BMW 540i so I had to go buy a gallon of green collant since that is what is in from the factory. It was $35. I spent $67,000 on this car so I am not about to run it out of collant and burn the engine up or use a different kind of coolant to save a few dollars. You only live once.

[M3SQRD]

This! Check your charge cooler because if it’s leaking it’s going straight into the engine.

Originally Posted by Slo_F80_Mike

You might wanna check your charge cooler if that's the tank which is low (smaller tank in the back by firewall). They have a tendency to leak the coolant leaks all into the intake ports and cylinders. If you're keeping the car for a while I'd recommend just upgrading the charge cooler.