[buster-riley]

Yikes the car tells me to have level checked. I ve about 7k miles on this 2018 330i X. Is this normal? There seem to be two tanks with screw tops? Why two? What should I do? Thx

[Billfitz]

Take it in to the dealer, you're covered by the maintenance agreement.

[DarkStarBimmer]

it could just be evap loss from seasons change, have you noticed a leak where you park?

[N420i]

Originally Posted by buster-riley

Yikes the car tells me to have level checked. I ve about 7k miles on this 2018 330i X. Is this normal? There seem to be two tanks with screw tops? Why two? What should I do? Thx

Tons of B58s are having this problem. It appears to be that they are underfilled or improperly bled at the factory and after a few thousand miles from new the level drops. It gets refilled for free at the dealer and that's that.

On the other hand, there are some B58s and B48s, like mine, that just seem to eat the coolant. We've refilled or taken the car to the dealer to be refilled and tested many times and the coolant requires refilling every few thousand miles. Nobody knows where it goes... No apparent leaks, no puddles in the floor, no splatter in the engine bay...

There are several theories floating around besides the factory underfilling.
Some people have found spotting from dry coolant around the reservoir cap, suggesting the caps leak.
There have been reports of turbos being replaced because of a leaky seal in the cooling circuit, where water was just getting burnt by the turbo. (This was in Germany apparently)
There have also been reports of the leaky EGRs being at fault...

BMW still won't issue an official statement/recall/whatever, even though it seems to be a pretty widespread occurrence.

I took mine to the dealer, they kept it for 4 days, ran all sorts of pressure tests, coolant system tests and diagnostics which apparently even required authorization from German HQ and according to them there is absolutely nothing wrong with the car, I should just take it back to them to add more coolant when the level drops. I think this is a less than optimal solution but for the moment I just keep an eye on the coolant level and top off as required myself...

[buster-riley]

Thanks for all the info. I topped it off with distilled water last night after it cooled down. It took 3/4 of a liter. That seems like a lot to me. Is it? Oddly when I started the car to move it a bit to get to the hood the "warning" was gone. That shouldn't happen should it? Also there are two arrows to align when closing. It seems that they were not as lined up when I opened it as when I closed it I really should have snapped an iPhone picture. One last thing I could swear that there was a vacuum in there when I opened it. Is that normal? Thx to all.

[buster-riley]

A bit off topic. Is there a long description of the B48 anywhere. I have a nice document describing the N55 but can't seem to locate the equivalent document for the B48. A water cooled intercooler? Really? Thx.

[rjd_F30]

https://f30.bimmerpost.com/forums/sh....php?t=1269118

First link (full technical guide [PDF]) in that thread.

[Billfitz]

Originally Posted by buster-riley

I topped it off with distilled water last night after it cooled down. It took 3/4 of a liter.

That's probably OK in Mississippi, not so much in Minnesota. You'd better add an equal amount of anti-freeze ASAP. The vacuum is normal, it's a sealed system.