For starters you should do a wipe down of your engine bay EVERY time you wash your car. And I hope you hand wash it yourself and don't use an automatic swirl maker wash. If you do this you will never need to deep clean your engine and will notice issues and be able to prevent them from becoming a major problem. The cap is usually the issue with the B58.. Replacing it tends to fix the the problem.. Just make SURE to wipe down the white residue or else the new cap won't have a tight seal and you will still have the same issue. Also do note that the cap will be harder to unscrew when the engine is HOT. This does not mean the cap is bad, it is by design in order to make sure hot, pressurized coolant does not explode in your face. If the cap is tough to remove when the engine is cold than you got either a bad seal (get new cap) or there is a lot of white gunk (dry coolant) developed around the cap. Start by cleaning the cap and the tank. Check again in about 2 to 3 weeks (around the time of your next wash) if you have the same problem then replace the cap and make sure clean the area around tank well. 50/50 mix means coolant and DISTILLED water.. DO NOT use tap. The minerals in tap water can damage your cooling system.
Actually that's wrong and the most terrible advice you can give with an engine made out of aluminium and/or magnesium.. Distilled water eats through aluminium/magnesium because it has no minerals itself, it kind of binds to the minerals in the engines. That's why you DON'T use it with these engines. The B58 is an aluminium engine, diesels or many other petrol engines aren't, there you can go for distilled water.
@@vinniw.3848 No, you are completely wrong there. It's the various minerals in tap water that can cause corrosion. Distilled water will not cause corrosion to the engine or radiator.
@@cfaul100 No, it won't corrode because you dont put pure water, it's mixed with coolant which prevents corrision in the first place. Sorry to tell, but you are completely wrong about that one. Also, you can't ignore the fact that distilled water is bad for aluminium/magnesium engines. Even BMW itself says NOT to use distilled water with the B58, so don't provide false-information just because you sometimes hear that you have to put distilled water in it
@@vinniw.3848 you are seriously wrong with the aluminium/magnesium binding stuff. the only reason bmw tells you not to use distilled only is because antifreeze has corrosion protection AND additives that keep the water pump lubricated.
Its the cap. When you are unscrewing it I can see it's squeaking and having irregular resistance. I had the same issue. A new cap and its much smoother to unscrew and solved the missing coolant issue.
I measured long term and came to about 1 Liter for about 20.000 Km. Normal, just like oil consumption is normal as well. Coolant has a low evaporation rate, never the less it does evaporate. People think the system is closed, but it is not. The system is pressurized, but there are temperature-pressure spikes and the related vapor is being vented via the built-in valve in the cap.
I had the same thing happen. No much residues like your car. But had to top it up with BMW orginal coolant with a distilled water 50/50 mix. Now I check schedule a check every end off month. I noticed not very to no loss. But in a 3 month's time. There is a loss about roughly 50ml give or take.
My 2017 b46 is slowly losing coolant from the high temp cooling circuit. After taking off the charge pipe and lower splash shield and really digging deep i finally found sgns of dried coolant residue by the water pump. Only got 40k miles on it but I'll be changing out the thermostat and water pump and hoses. Might do the oil filter housing since it'll be accessible
Coolant warning light went on. Had low coolant, about 1.5l. My AC was acting up. After recharging, AC worked as it should. BMW wanted $300 just to check (look) AC system.
The sensors are so good for the coolant reservoir it will tell me the second it gets below min. on the fill mark. But I can confirm I’ve had to put coolant in the reservoir on 3 separate occasions in 2 years. I noticed it only happens during winter. Each time I’ve only needed a few ounces to get the fluid level to max.
Most of the time it will be from the coolant cap change it.if still loosing coolant try bleeding coolant to remove bubles if doesnt work that means you have a leak in your coolant system check it out.
Hi Reg, Thanks for the video. I only heard about this issue a month or so ago and hence checked and my main coolant tank had lost about the same as yours after 3 years and 8000 miles so i just topped up with BMW coolant at 50-50 mix. I was told by BMW to also check the smaller tank as thats for the intercooler i believe and should be checked too as this has the same yellow min/max value. Mine was ok in the smaller tank. I also think its the same coolant mix but just thought id mention / check to see if you checked that too or anyone else has?. Thanks again. Drive safe, stay safe.
Thanks KB. To be completely honest, I’ve not checked the other tank. I definitely will now though. Yeah 50/50 mix. To be completely honest I didn’t accurately measure it. I did by eye, but as long as it’s roughly 50/50, it will be fine 😀
@@roadreg1820 my cousin has an m240i same engine the smaller tank is apparently the one that gets alot of people as the big tank should be able to give a low level light on the dash however the smaller tank doesnt and it radiators are prone to have stones hit them resulting in leaks from what we've read but evaporation is defiantly the more common reason for low coolant
I've had a similar issue on my E90 with the M57, but the issue was a busted o-ring sealing the tube from the EGR cooler to the thermostat housing. These engines should never "eat" or "use" coolant.
Different engine altogether m57 strong engine yes its diesel this is the 3.0 teinpower turbo petrol not the economy option and id say best engine to date
I just carry a jug of green coolant in the trunk & top off whenever I get the warning. It’s mostly on cold days/mornings. Sometimes I’ll let it heat up, park, and then restart the vehicle & it’ll disappear
In B48 is the same. However if your level goes down the car warns you thanks to a special sensor. My coolant level also tends to go down on its own and I check it often (once a month) to avoid the risk of being far from home with the low fluid warning. The next time I leave it in BMW for a service I have it checked because I don't think it's normal.
No, the BMW garages are full due to the recalls of the diesel AGR radiators, I asked for an appointment with a courtesy car and it takes 2 months to wait@@alexcorea9770
@@alexcorea9770they all do this, even the g series with b58s. I know 3 people with b58 variants and all of them had the same coolant loss. It’s a tiny amount but enough to trip the sensor
Had this on my 240 as well, less than 7k on the clock. Car started holding power back quite a bit. Took it in and the coolant was pretty much empty! Never had that on any of my cars nevermind a pretty much brand new one. No leaks found and no real explanation but I do check it now even though it's never done it again in years. Was shocked😂
Yeah - that’s why I made this video, just for people who might not be aware of this ‘issue’. Hopefully will help prevent other people leaving it too long with no coolant. Very odd isn’t it!
@@roadreg1820 Yeah definitely a good idea for potential buyers and newer owners, had no idea about it myself before it happened and then seen all the posts about it after I looked into it. Definitely strange. Good how the ecu pulls the power back when it happens though, mine wasn't overheating or anything. I noticed something was definitely up and I wasn't just going mad when I was driving on the motorway late at night and it felt much faster like it was before, was obviously getting much more cooling!
Another issue some have is the cap is impossible to get off. Yours seems really easy to come off. Mine is rock solid so I have to leave it to BMW to check but I might get a new cap to see if it fixes it. Job for the morning
@@NaCxDaVe Cap is supposed to be difficult to unscrew when the engine is hot. If it is hard to remove when engine is cold than you most likely have a bad seal (cap).
My 2017 b46 coolant light was coming on, took it to the shop and they said the coolant was leaking from a hose going into the turbo. Got it back and the light came back on, took it back and now they’re saying coolant is a leaking from the transmission coolant line 😩
I check mine every week, especially now we are in winter. For anyone who is unsure : you absolutely, unequivocally, can use tap water. I work in the motor trade, and I promise you now - using tap water will not cause any damage to your engine...I've seen tap water used in normal engine coolant systems, and high performance Aston Martin engines - there is NO issue with using tap water.
So the bigger resivore is for coolent but what is the smaller resivore for? I have a 2020 530i and I don't know which one to put the coolent in the big resivore or the small one
Yes it does but only for the MAIN coolant tank, not the intercooler.. This is why I always tell people to check your engine bay when ever you wash your car and unscrew those caps.
Many say you can't mix, if it's just a little bit it's not bad at all. Flushing is another matter of course. I got to à tank station and would take blue one but owner there said it was not good for the car, red one was for high performance car he said. In the end its mainly build out of water with just a colour in it. Big cap was also not empty just a little lower then it should be so it's not that I switched it from blue to red.
NO!! You must only use BMW coolant or BMW approved blue coolant in these engines. Absolutely do not mix two different coolant types together! The coolants can mix and form a gel which blocks your whole coolant system and will ruin your engine. Why would you take advice from a filling station owner instead of a mechanic?? 🙄
Mate. Bmw use the blue coolant on all cars that i know of but especially these! Don't mix coolant, saying red is for performance cars is bullshit red degrades the seals! You use blue with a 50/50 mix with distilled water only
@@Magezzz when I made the comment was some time ago, I've got the OEM coolant for a while now. Used rain water to fill half. Tell me? Using distilled water is to protect it against chalk isn't it?
BMW uses two coolants one is blue and the newest one is green. I know my 19 F32 440 has the green coolant in it and yes they can be mixed. IF your car is 2018 or newer than it will use the green coolant.
Nice. It’s only small amounts but if you don’t know about it, you’ll end up having zero coolant, but even then the computer would warn you before it’s too late.
Yes it's the same cap and coolant reservoir design. Problem is across all platforms. Luckily the caps are cheap and if you are under warranty than most dealers will just give you the cap and not have you wait.
@@ashegheaty I seen this issue in the new models as well.. Problem is time based. The seal on the main coolant tank cap starts to fail over time.. Eventually you will probably have this issue. Again caps are cheap and covered under warranty so it's no a major issue.. Just check your coolant tanks from time to time.
ONLY for the main coolant tank.. The smaller tank (intercooler) will not give you a notification but there is rarely an issue with the cap for the smaller tank.
Mate your cap is definitely leaking look at all the white residue around the bottle neck, there is a problem with the seals on the cap BMW revised the cap in 2019. Mine was about an inch below minimum when I checked it so I went and bought a new cap from BMW for £17. No probs since 👍🏻
Thanks for the heads up. I did notice that my coolant level is low a lot. I’m glad it’s not just mine. I really like my car 👍🏾
Developed this problem with the m340 and noticed the big tank was very low didn't throw any warning though.
For starters you should do a wipe down of your engine bay EVERY time you wash your car. And I hope you hand wash it yourself and don't use an automatic swirl maker wash. If you do this you will never need to deep clean your engine and will notice issues and be able to prevent them from becoming a major problem.
The cap is usually the issue with the B58.. Replacing it tends to fix the the problem.. Just make SURE to wipe down the white residue or else the new cap won't have a tight seal and you will still have the same issue. Also do note that the cap will be harder to unscrew when the engine is HOT. This does not mean the cap is bad, it is by design in order to make sure hot, pressurized coolant does not explode in your face. If the cap is tough to remove when the engine is cold than you got either a bad seal (get new cap) or there is a lot of white gunk (dry coolant) developed around the cap. Start by cleaning the cap and the tank. Check again in about 2 to 3 weeks (around the time of your next wash) if you have the same problem then replace the cap and make sure clean the area around tank well.
50/50 mix means coolant and DISTILLED water.. DO NOT use tap. The minerals in tap water can damage your cooling system.
THANK YOU FOR YOUR SERVICE 🌍🌞
Thank you very much for this, you saved me from cooking my engine!
I had this issue on my 2019 240i in 2022. Topped up and it's been good since 🤞. Cheers Reg👍
Really glad to hear that. Mine is the same, just the very occasional top up. No drama :)
Don't mix coolant using tap water. Use distilled only.
🤦🏽♂️you really think dealerships run to the store and grab bottles of distilled water?? Not a chance.
Actually that's wrong and the most terrible advice you can give with an engine made out of aluminium and/or magnesium.. Distilled water eats through aluminium/magnesium because it has no minerals itself, it kind of binds to the minerals in the engines. That's why you DON'T use it with these engines. The B58 is an aluminium engine, diesels or many other petrol engines aren't, there you can go for distilled water.
@@vinniw.3848 No, you are completely wrong there. It's the various minerals in tap water that can cause corrosion. Distilled water will not cause corrosion to the engine or radiator.
@@cfaul100 No, it won't corrode because you dont put pure water, it's mixed with coolant which prevents corrision in the first place. Sorry to tell, but you are completely wrong about that one. Also, you can't ignore the fact that distilled water is bad for aluminium/magnesium engines. Even BMW itself says NOT to use distilled water with the B58, so don't provide false-information just because you sometimes hear that you have to put distilled water in it
@@vinniw.3848 you are seriously wrong with the aluminium/magnesium binding stuff. the only reason bmw tells you not to use distilled only is because antifreeze has corrosion protection AND additives that keep the water pump lubricated.
Its the cap. When you are unscrewing it I can see it's squeaking and having irregular resistance. I had the same issue. A new cap and its much smoother to unscrew and solved the missing coolant issue.
Having the same issue now low coolant level with no leaks??
@@wilderfelix9696 change the cap
Link?
I'll try
Hey,
I also replaced it. Is it normal for my new cap to move more, it seems like it is not fixed like my old cap and comes off much easier
I measured long term and came to about 1 Liter for about 20.000 Km. Normal, just like oil consumption is normal as well. Coolant has a low evaporation rate, never the less it does evaporate. People think the system is closed, but it is not. The system is pressurized, but there are temperature-pressure spikes and the related vapor is being vented via the built-in valve in the cap.
I had the same thing happen. No much residues like your car. But had to top it up with BMW orginal coolant with a distilled water 50/50 mix. Now I check schedule a check every end off month. I noticed not very to no loss. But in a 3 month's time. There is a loss about roughly 50ml give or take.
Same in mine - seems to be a ‘standard feature’
My 2017 b46 is slowly losing coolant from the high temp cooling circuit. After taking off the charge pipe and lower splash shield and really digging deep i finally found sgns of dried coolant residue by the water pump. Only got 40k miles on it but I'll be changing out the thermostat and water pump and hoses. Might do the oil filter housing since it'll be accessible
Coolant warning light went on. Had low coolant, about 1.5l. My AC was acting up. After recharging, AC worked as it should. BMW wanted $300 just to check (look) AC system.
The sensors are so good for the coolant reservoir it will tell me the second it gets below min. on the fill mark. But I can confirm I’ve had to put coolant in the reservoir on 3 separate occasions in 2 years. I noticed it only happens during winter. Each time I’ve only needed a few ounces to get the fluid level to max.
That’s good to know! Yeah it’s never much, but better to know than not 😁
es cierto, el mio tambien baja el nivel, lo revisare mañana nuevamente, siempre revisar con el motor bien frio
Most of the time it will be from the coolant cap change it.if still loosing coolant try bleeding coolant to remove bubles if doesnt work that means you have a leak in your coolant system check it out.
Hi Reg, Thanks for the video. I only heard about this issue a month or so ago and hence checked and my main coolant tank had lost about the same as yours after 3 years and 8000 miles so i just topped up with BMW coolant at 50-50 mix. I was told by BMW to also check the smaller tank as thats for the intercooler i believe and should be checked too as this has the same yellow min/max value. Mine was ok in the smaller tank. I also think its the same coolant mix but just thought id mention / check to see if you checked that too or anyone else has?. Thanks again. Drive safe, stay safe.
Thanks KB. To be completely honest, I’ve not checked the other tank. I definitely will now though. Yeah 50/50 mix. To be completely honest I didn’t accurately measure it. I did by eye, but as long as it’s roughly 50/50, it will be fine 😀
@@roadreg1820 my cousin has an m240i same engine the smaller tank is apparently the one that gets alot of people as the big tank should be able to give a low level light on the dash however the smaller tank doesnt and it radiators are prone to have stones hit them resulting in leaks from what we've read but evaporation is defiantly the more common reason for low coolant
I've had a similar issue on my E90 with the M57, but the issue was a busted o-ring sealing the tube from the EGR cooler to the thermostat housing. These engines should never "eat" or "use" coolant.
Different engine altogether m57 strong engine yes its diesel this is the 3.0 teinpower turbo petrol not the economy option and id say best engine to date
I just carry a jug of green coolant in the trunk & top off whenever I get the warning. It’s mostly on cold days/mornings. Sometimes I’ll let it heat up, park, and then restart the vehicle & it’ll disappear
Yes same it doesn’t have to be bmw coolant too i use prestone
Check the O rings, line for the turbo 👍👍
Turbo is golden thanks 🤩
In B48 is the same. However if your level goes down the car warns you thanks to a special sensor. My coolant level also tends to go down on its own and I check it often (once a month) to avoid the risk of being far from home with the low fluid warning. The next time I leave it in BMW for a service I have it checked because I don't think it's normal.
@AzurikTube any updates
No, the BMW garages are full due to the recalls of the diesel AGR radiators, I asked for an appointment with a courtesy car and it takes 2 months to wait@@alexcorea9770
@@alexcorea9770they all do this, even the g series with b58s. I know 3 people with b58 variants and all of them had the same coolant loss. It’s a tiny amount but enough to trip the sensor
Better to buy coolant pre mixed bro. And change the cao the fault is in the cap hence the residue.
Your cap is leaking you can see the crust on the threads
but can you mix the antifreeze blue with destilirian waser G48?
What is that thing next to it for?
Had this on my 240 as well, less than 7k on the clock. Car started holding power back quite a bit. Took it in and the coolant was pretty much empty! Never had that on any of my cars nevermind a pretty much brand new one. No leaks found and no real explanation but I do check it now even though it's never done it again in years. Was shocked😂
Yeah - that’s why I made this video, just for people who might not be aware of this ‘issue’. Hopefully will help prevent other people leaving it too long with no coolant. Very odd isn’t it!
@@roadreg1820 Yeah definitely a good idea for potential buyers and newer owners, had no idea about it myself before it happened and then seen all the posts about it after I looked into it. Definitely strange. Good how the ecu pulls the power back when it happens though, mine wasn't overheating or anything. I noticed something was definitely up and I wasn't just going mad when I was driving on the motorway late at night and it felt much faster like it was before, was obviously getting much more cooling!
Another issue some have is the cap is impossible to get off. Yours seems really easy to come off. Mine is rock solid so I have to leave it to BMW to check but I might get a new cap to see if it fixes it. Job for the morning
@@NaCxDaVe hope it gets sorted 🤞
@@NaCxDaVe Cap is supposed to be difficult to unscrew when the engine is hot. If it is hard to remove when engine is cold than you most likely have a bad seal (cap).
What’s that pressure release knob with the cross for a Phillips head screwdriver slot called? On the top of the coolant container
Bleed screw
Clean that engine!
Haha guilty
😄
bruh it is the coolant cap you can see all that dried coolant in the vid
I recently changed my large coolant cap and currently appears to have slowed any coolant loss, coincidence, who knows 👍
I think the same thing happening to my m4 i keep losing coolant but no leaks no weird smell but the cap feels really lose
@@picogeeevlogs8766 is the cap feeling lose also with the new cap?
Ya it is bro
@@picogeeevlogs8766 I also replaced it, with warm engine it is not so loose. I think it's normal
Ya it ended up being my turbo lines bro the o rings smh cost alot to replace
I add distilled water time to time
My 2017 b46 coolant light was coming on, took it to the shop and they said the coolant was leaking from a hose going into the turbo. Got it back and the light came back on, took it back and now they’re saying coolant is a leaking from the transmission coolant line 😩
That sucks. That’s a real shame !
Replace your cap, my guy. Coolant is escaping through the seal, hence the crystallization
Exactly! Had same issue on my recently bought 340i. I went with aftermarket cap as originals keep failing obviously. Issue solved. Cheap fix :)
I check mine every week, especially now we are in winter.
For anyone who is unsure : you absolutely, unequivocally, can use tap water.
I work in the motor trade, and I promise you now - using tap water will not cause any damage to your engine...I've seen tap water used in normal engine coolant systems, and high performance Aston Martin engines - there is NO issue with using tap water.
just no........ ppl use distilled only this man is a troll
Sad troll
@f32440i you're a troll...I am speaking from having first hand experience with this engine. Tap water has been fine for the past 4 years.
The little white flakes around the mouth of the tank are indicative of a coolant leak from the filler cap. It looks like you need a new filler cap.
Ok thanks for the advise 😁
What cap do you buy though? The exact same cap or a aftermarket one?
So that reservoir next to that?? Do you add coolant in there also?? BMW just told me add to both. ???
Yes if it needs it, but this one doesn’t seem to use any coolant really.
So the bigger resivore is for coolent but what is the smaller resivore for?
I have a 2020 530i and I don't know which one to put the coolent in the big resivore or the small one
The smaller one is for the charge cooler I think. That one doesn’t really fluctuate.
Big one is the main cooling, the small one is the low pressure coolant line for the turbo.
What coolant are you using? Thanks
BMW genuine coolant. It’s blue
Does the car give any alarm or notification of low coolant level in time? Or is the low level alarm way too low to wait for?
Yes it does. I would rather that messege not come up, as it would be super low. I tend to check it every 2 months maximum
@@roadreg1820 Yeah makes sense. BMW also sells coolant which I think is premixed. Not sure about how exspensive it..
mine give it 1 month ago
Yes it does but only for the MAIN coolant tank, not the intercooler.. This is why I always tell people to check your engine bay when ever you wash your car and unscrew those caps.
Use the manufacturer coolant , bmw recommends it , doesn’t recommend doing your own mixes
@@AlejandroJaime213 I do, it doesn’t come pre mixed. It’s 50/50 ratio. That’s what they recommended.
Lots of crud around that coolant opening. Hope none falls into your coolant.
All good 👍
What's the smaller reservoir next to it?
Charge Cooler I think
blown headgasket
No head gasket is fine.
what about the smaller one ?
Yeah did you find out the smaller one
Maybe it's going into the engine! I know someone with a head failure on a M240i😱
It’s not, engine is running like a dream as we speak. Just needs the occasional light top up of coolant.
Many say you can't mix, if it's just a little bit it's not bad at all. Flushing is another matter of course. I got to à tank station and would take blue one but owner there said it was not good for the car, red one was for high performance car he said. In the end its mainly build out of water with just a colour in it. Big cap was also not empty just a little lower then it should be so it's not that I switched it from blue to red.
NO!! You must only use BMW coolant or BMW approved blue coolant in these engines. Absolutely do not mix two different coolant types together! The coolants can mix and form a gel which blocks your whole coolant system and will ruin your engine. Why would you take advice from a filling station owner instead of a mechanic?? 🙄
Mate. Bmw use the blue coolant on all cars that i know of but especially these! Don't mix coolant, saying red is for performance cars is bullshit red degrades the seals! You use blue with a 50/50 mix with distilled water only
@@Magezzz when I made the comment was some time ago, I've got the OEM coolant for a while now. Used rain water to fill half. Tell me? Using distilled water is to protect it against chalk isn't it?
@@bradofwar5960 Minerals and stuff yes
BMW uses two coolants one is blue and the newest one is green. I know my 19 F32 440 has the green coolant in it and yes they can be mixed. IF your car is 2018 or newer than it will use the green coolant.
My bm’s coolant cap is even harder than that to open, don’t know why.
Anyone ?
Change your coolant cap
Thanks mate! I would add g30 or g31 hastags as nobody on YT fill coolant on those ;)
Nice. It’s only small amounts but if you don’t know about it, you’ll end up having zero coolant, but even then the computer would warn you before it’s too late.
Can anyone tell me please for what the second tank is ?
I think the charge cooler. I could be wrong tho!
Why coolant is this color?
Bmw coolant
Is this the same for the B58TU1 engine aswell. I have a 2021 M340i
sorry 2020
I have a white on black 2021 M340 with 7400 km on it in 3 months and has not lost a drop of coolant yet , cheers .
Yes it's the same cap and coolant reservoir design. Problem is across all platforms. Luckily the caps are cheap and if you are under warranty than most dealers will just give you the cap and not have you wait.
@@ashegheaty I seen this issue in the new models as well.. Problem is time based. The seal on the main coolant tank cap starts to fail over time.. Eventually you will probably have this issue. Again caps are cheap and covered under warranty so it's no a major issue.. Just check your coolant tanks from time to time.
Am not sure about the TU B58.
Love all the B58 huggers making excuses...also has a track record of oil consumption
No oil consumption issues on B58’s. Mine hasn’t used a drop. The coolant loss, is clearly down to the cap.
@roadreg1820 it has been reported on Gen 1s...plastic parts everywhere including oil pump
These caps are garbage. I know of several people who replaced them and it helped.
The car will notify you if the level drops below an adequate level
Yup, don’t want it to get to that point though, so best to check once every few months just to be safe.
ONLY for the main coolant tank.. The smaller tank (intercooler) will not give you a notification but there is rarely an issue with the cap for the smaller tank.
The caps obviously goosed or the system is over pressuring
Cap. Everything is fine - just a very occasional top up.
@@roadreg1820 the white stuff around the threads and on tank is coolant leaking from the cap.
@@AnthGott cap has been replaced since then
@@roadreg1820which cap did you replace it with?
@@Isidropatino standard oem bmw cap
I’m sure there’s a leak! It’s a BMW
There’s no leak.
Than is for posting this so many rubbish videos out there now my head is sorted
I got a leak on my g30 17
Mate your cap is definitely leaking look at all the white residue around the bottle neck, there is a problem with the seals on the cap BMW revised the cap in 2019. Mine was about an inch below minimum when I checked it so I went and bought a new cap from BMW for £17. No probs since 👍🏻
Thanks James, will get on getting a new cap
Yeah that’s what I thought too
thanks, I didn't know that, gonna get a new cap!