[chassis]

Just received the warning message in the original post. Reservoir clearly low, approx 1 qt low.

No obvious drips on the garage floor, no visible leaks underhood and no obvious smell from tailpipe or HVAC inside vehicle. Will top it up and monitor.

[TXSchnee]

Older thread, but want to double check. Just got this message this morning, is BMW coolant absolutely necessary, or if I use Prestone, is that fine? I have never seen a vehicle require OEM antifreeze before.

[freshxdough]

Originally Posted by TXSchnee

Older thread, but want to double check. Just got this message this morning, is BMW coolant absolutely necessary, or if I use Prestone, is that fine? I have never seen a vehicle require OEM antifreeze before.

Depending on the year of your vehicle you may need green coolant. Recommend OEM. If it's just a little low just add water until cold fill level. I would choose water over adding a non OEM coolant

[TXSchnee]

Originally Posted by freshxdough

Depending on the year of your vehicle you may need green coolant. Recommend OEM. If it's just a little low just add water until cold fill level. I would choose water over adding a non OEM coolant

It is an '18 M40i. When I checked levels it was the blue coolant.

[chassis]

Originally Posted by TXSchnee

Older thread, but want to double check. Just got this message this morning, is BMW coolant absolutely necessary, or if I use Prestone, is that fine? I have never seen a vehicle require OEM antifreeze before.

I prefer to use OEM coolant. M-B for example has fairly complex fluid requirements that vary over the years.

When I got the low coolant message on our X3, I drove to the dealer and they topped it up for me free of charge in the service writeup bay. Pretty nice.

[freshxdough]

Originally Posted by TXSchnee

It is an '18 M40i. When I checked levels it was the blue coolant.

I would suggest topping up with water or going to the nearest dealer. Would not suggest mixing coolants. This Is not recommended by BMW as well.

[Pray for Mojo]

Its under warranty, go to the dealer, it shouldn't lose coolant so they will top it off for free.

[Alias1431]

I just use vodka. Any ol' cheap stuff'll do. Really sheds the heat well.

[BMWGuySweden]

Update on this thread. Just around this time last year I got the coolant level low warning. I brought into the dealer and they couldn't find anything wrong. They just filled it up. Now 1 year later I got the same warning. Does anyone have the same problem and know what's wrong?

[Pray for Mojo]

Here's some of the potential sources.

[R N M]

Just started to get this warning on my 2020 X3 which has 22k miles. It’s strange because I just did my 2nd year service.

Hopefully dealer will top it off and that will solve the issue.

[OPF]

Originally Posted by Pray for Mojo

Here's some of the potential sources.

Great video. Just came out of the BMW garage yesterday, and they booked me for a pressure test in January. They added more than 1 liter of coolant fluid to the system.
I had this warning 3 times on my 2019/X3M40i/ with just over 35 000 km.

[steheb]

Originally Posted by freshxdough

I would suggest topping up with water or going to the nearest dealer. Would not suggest mixing coolants. This Is not recommended by BMW as well.

I know this is old post, but I would not add water to cooling system myself. While average engine temp is 90-100C, some very local parts around cylinders could reach 150+C easily. This is why BMW coolant has boil temperature around 180C. Adding water decreases coolant boiling temperature, thus can cause damage of critical parts.

[freshxdough]

Originally Posted by steheb

I know this is old post, but I would not add water to cooling system myself. While average engine temp is 90-100C, some very local parts around cylinders could reach 150+C easily. This is why BMW coolant has boil temperature around 180C. Adding water decreases coolant boiling temperature, thus can cause damage of critical parts.

If your cylinder head is reaching 150C you have bigger problems. 150C is considered damaging. I know this because on the B46/B48 engine in the F30/F32 when the coolant hose between the cylinder head and the expansion tank breaks the engine losses all coolant very quickly and overheats if the customer doesn't stop the vehicle. You will have faults if the cylinder head temp reaches a specific temperature. I've seen these range from 150C to 178C. Your engine coolant should NEVER be reaching 150C in any measurable location.

Also the water/coolant mixture doesn't affect the boiling point as much as the freezing point. For example, 100% water mixture is 212F as we all know. 50/50 is ~225F boiling point.

[steheb]

Originally Posted by freshxdough

If your cylinder head is reaching 150C you have bigger problems. 150C is considered damaging. I know this because on the B46/B48 engine in the F30/F32 when the coolant hose between the cylinder head and the expansion tank breaks the engine losses all coolant very quickly and overheats if the customer doesn't stop the vehicle. You will have faults if the cylinder head temp reaches a specific temperature. I've seen these range from 150C to 178C. Your engine coolant should NEVER be reaching 150C in any measurable location.

Also the water/coolant mixture doesn't affect the boiling point as much as the freezing point. For example, 100% water mixture is 212F as we all know. 50/50 is ~225F boiling point.

My example was more like extreme, but it represents the idea. If you pull the fun pedal for some time, cylinder head can go hot (water/coolant isn’t that efective to quickly transfer the heat from metal).

Adding 50/50 water/coolant can decrease your realistic boiling point to more like 130-150C (when pressurised in coolant loop the point is higher). So even if some metals parts reach 130C, there might be boiling and vapour which is released from the system through vent screw.

[GriffoX3]

Had same message after a long run across Spain. Opened coolant reservoir next day when engine was cold and has not reappeared since. More than likely just an air lock as others have stated.