[BMW012]

2021 M550i with 6004 miles. Just received the "add coolant" warning this morning. Was aware this was common but does it happen at 6k miles?

I do know it did get serviced at around 3k miles (5 months ago) when I took over the vehicle. Not sure exactly what was done but at least an oil change I believe.

Would coolant have been topped off then or probably not? And how long can I go on driving before I can get it serviced?

[AP]

This seems to be a common issue, just search through these threads and you'll find some

Had this myself which turned out to be a faulty reservoir

What I would say is :-

Car is under warranty so no worries about cost

Don't be fobbed by dealer if they say it's normal and offer to top it up

Coolant should leak out at all , it's a sealed system

If you do want to buy some coolant , bmw parts sell some .

Guess it depends how low it really is, can you see at all in the reservoirs?
Probably ok to drive to dealers gently but at first sign of temp gauge climbing, stop

[Pierre Louis]

The expansion tank provides a relief function from too high a pressure in the cooling system and is therefore not a completely sealed system:

https://www.bimmerworld.com/About-Us...g-System-Tech/

"BMW Expansion Tank
The expansion tank is also known as the overflow tank or coolant reservoir. As cooling demands change the level of coolant in this tank will go up or down. It's also a place where coolant can spill into when system pressure is too high. The cap on the tank serves a vital purpose of venting/controlling system pressure. Too much pressure needs to be vented to prevent a failure. Too little pressure leads to poor system performance. For this reason the expansion tank, cap, and bleed valve are the highest points of the cooling system.

The expansion tank on 1992+ models seems to be the most common source of leaks and broken plastic. It must be a material issue or quality control problem that allows the plastic to split or warp and cause leaks. Failures are not an epidemic and they typically last 5-6 years so maybe that's just their expected demise. Unless the car is tracked or raced, most people simply reinstall an OEM plastic tank with the expectation that it will fail and need replacement again in the future. For ultimate reliability, but higher cost, we offer an aluminum expansion tank for some models."

[BMW012]

just started my car after lunch and now the message is gone...

[Mandingo9]

Does burning/smoking coolant have a distinct smell?

[HerkHealer]

Originally Posted by Mandingo9

Does burning/smoking coolant have a distinct smell?

Yes! It smells awful, like toxic. It makes your eyes water its so bad.

My car has been in twice now for "low coolant" and I STILL to this day get that sweet coolant smell inside my garage after a spirited drive. Each time they pressure test the system and say it's good to go. It's bullshit. You cant smell coolant without it leaking out somewhere. The M5 guys have the same thing. Its normally the expansion tank having micro cracks that expand when hot.

Getting back to the smell. Both me and Joe had our cars in for that toxic smell.
Its coolant that pools and starts cooking in the Deep V section of the motor.
BMW even has a TSB on it because its so common. As soon as I mentioned it to my SA, he knew exactly what to do to fix it. They clean that V area up and back to no smell again.

BTW OP my car is a 2020 with 13,600 miles on it. And I've had low coolant twice now.

[HerkHealer]

Originally Posted by BMW012

2021 M550i with 6004 miles. Just received the "add coolant" warning this morning. Was aware this was common but does it happen at 6k miles?

I do know it did get serviced at around 3k miles (5 months ago) when I took over the vehicle. Not sure exactly what was done but at least an oil change I believe.

Would coolant have been topped off then or probably not? And how long can I go on driving before I can get it serviced?

You're right on the edge of needing to top off. It will come back, trust me.
I've done it twice now. Your car should have the green coolant.
I bet you have a hard time getting the cap off. Mine was "glued" to the threads with dried coolant. I had to use adjustable pliers just to get the cap off.

[Mandingo9]

Originally Posted by HerkHealer

Yes! It smells awful, like toxic. It makes your eyes water its so bad.

My car has been in twice now for "low coolant" and I STILL to this day get that sweet coolant smell inside my garage after a spirited drive. Each time they pressure test the system and say it's good to go. It's bullshit. You cant smell coolant without it leaking out somewhere. The M5 guys have the same thing. Its normally the expansion tank having micro cracks that expand when hot.

Getting back to the smell. Both me and Joe had our cars in for that toxic smell.
Its coolant that pools and starts cooking in the Deep V section of the motor.
BMW even has a TSB on it because its so common. As soon as I mentioned it to my SA, he knew exactly what to do to fix it. They clean that V area up and back to no smell again.

BTW OP my car is a 2020 with 13,600 miles on it. And I've had low coolant twice now.

Interesting. Don't think I've encountered it then. I have a 2022 with 8k miles no lights or anything, yet it seems.

[HerkHealer]

Originally Posted by Mandingo9

Interesting. Don't think I've encountered it then. I have a 2022 with 8k miles no lights or anything, yet it seems.

I think its hit or miss. Joe's problem was his turbo lines leaking not the expansion tank. Which is VERY common for the 17-19 s. years.
Our motors were upgraded to steel lines.
If you dont smell coolant (sweet smell) in garage after driving it hard, you should be good to go. Probably worth a peek inside the coolant tank at minimum though. Like I said it may be a bitch to get off. Mine certainly was.
I had to buy a new cap it was so bad.

The odd thing for me is even though I can smell it now and then, I never see anything on the garage floor. It must be a very, very, small leak when things are hot.

[Mandingo9]

Originally Posted by HerkHealer

I think its hit or miss. Joe's problem was his turbo lines leaking not the expansion tank. Which is VERY common for the 17-19 s. years.
Our motors were upgraded to steel lines.
If you dont smell coolant (sweet smell) in garage after driving it hard, you should be good to go. Probably worth a peek inside the coolant tank at minimum though. Like I said it may be a bitch to get off. Mine certainly was.
I had to buy a new cap it was so bad.

The odd thing for me is even though I can smell it now and then, I never see anything on the garage floor. It must be a very, very, small leak when things are hot.

When I drive it hard theres the break in smell but different. I'd figure after 8k everything would be broken already so that's the reason I ask.

[HerkHealer]

Originally Posted by Mandingo9

When I drive it hard theres the break in smell but different. I'd figure after 8k everything would be broken already so that's the reason I ask.

If you have coolant cooking it smells REALLY bad. Like plastic burning or something similar. Like I said it was so bad my eyes were watering up.

[Mandingo9]

Originally Posted by HerkHealer

If you have coolant cooking it smells REALLY bad. Like plastic burning or something similar. Like I said it was so bad my eyes were watering up.

Mercifully nothing like that but at least now I know what'll be like.

[steve090619]

Originally Posted by BMW012

just started my car after lunch and now the message is gone...

Originally Posted by BMW012

just started my car after lunch and now the message is gone...

It will be back. Go to bmw and top off. I bought my own antifreeze, made 50:50 mixture and keep in My garage. Every fall when temp drops, i get that warning.

[BMW012]

Originally Posted by steve090619

It will be back. Go to bmw and top off. I bought my own antifreeze, made 50:50 mixture and keep in My garage. Every fall when temp drops, i get that warning.

Makes sense! temperature started dropping here in NJ. Picking up before end of day, BMW topped it off.

[430Scud]

Originally Posted by BMW012

just started my car after lunch and now the message is gone...

That would be because the fluid is warm and has expanded some. The warning will return after the car cools completely, such as overnight.

As others surmised, this always crops up in winter, as temps cool overnight. On my long term E39 I have had to add about a cup of diluted coolant every fall to address the warning light.

[jan_gabriel2000]

Same problem to me. I have filled up the coolant and after few months the message appeared again. Did it again and now it is fine....for how long i do not know. All the parts of the car are dry and no leak or something similar...

[Finny]

Originally Posted by jan_gabriel2000

Same problem to me. I have filled up the coolant and after few months the message appeared again. Did it again and now it is fine....for how long i do not know. All the parts of the car are dry and no leak or something similar...

I was doing this over a 12 month period - various theories from the mechanic. Ended up having to change the expansion tank - hopefully when I get it back next week it’ll be solved. Not a cheap part out of warranty and only 45k miles.

[Mandingo9]

Originally Posted by Finny

I was doing this over a 12 month period - various theories from the mechanic. Ended up having to change the expansion tank - hopefully when I get it back next week it'll be solved. Not a cheap part out of warranty and only 45k miles.

Ask them for a good faith warranty replacement. So few miles out of warranty with a known defect. They may cover it all or at worst, half.

[Oldgixxer]

Was one of the several issue's on my '20 550i,tech said its common and "don't worry" you won't toast a head gasket or piston. Could definitely smell that unmistakable sweet odor of coolant when parked in my garage a few days prior to the warning popping up on the dash

[Finny]

Originally Posted by Mandingo9

Ask them for a good faith warranty replacement. So few miles out of warranty with a known defect. They may cover it all or at worst, half.

Good thought but I have already paid them for the work - although I got it back more broken than before. I also misspoke - they only had to replace a hose but parts and labor put that around $500.