[LouK]

Originally Posted by The5rivers

2021 M5C, 13.7K miles. I had the "engine coolant level low" error message pop up after a cold start tonight for about 4 seconds that went away on its own. Temp outside was 34 degrees. I drove away and the error message didn't come back. Stopped and started a few more times while running errands and still nothing.

I'm going to check out the fluid level tomorrow and see if it's actually low but made an appointment with my dealer on Monday to check for a leak and going to show them the TSB and probably just push to get it replaced under warranty.

Same thing happened to me, stopped by the dealer as it was 5 min from my intended destination. Dealer topped off, said it didnt take much at all and "is not uncommon to need a little bit here and there". My tank doesnt appear to be failing ( no residue around it, or signs of leaking below) Car is going in later in the month for some other warranty fixes so we will see if that presents itself again.

[AHall]

Originally Posted by LouK

Same thing happened to me, stopped by the dealer as it was 5 min from my intended destination. Dealer topped off, said it didnt take much at all and "is not uncommon to need a little bit here and there". My tank doesnt appear to be failing ( no residue around it, or signs of leaking below) Car is going in later in the month for some other warranty fixes so we will see if that presents itself again.

I have added a little coolant maybe a total of 16 ounces over the almost three years I have had the car. No sign of any leaks, but because others have had tank failures I check it every now and then. If it is low I add some, mixed 50:50 of course.

[The5rivers]

Originally Posted by LouK

Same thing happened to me, stopped by the dealer as it was 5 min from my intended destination. Dealer topped off, said it didnt take much at all and "is not uncommon to need a little bit here and there". My tank doesnt appear to be failing ( no residue around it, or signs of leaking below) Car is going in later in the month for some other warranty fixes so we will see if that presents itself again.

Yeah as a follow-up to my original post, I took it in and it was basically empty. They tested it for leaks and couldn't find any. I showed them pictures of small amounts of white residue around the cap and some around the tank itself, but they couldn't find a leak and topped me off and told me to watch it.

Since then, the level has very slowly started to decline again, so I don't know if there's a small leak somewhere, or my cap is faulty, because I don't see any fluid on my garage floor, nothing in and around the engine, etc.

I already know I will be going back in again, and I kept the service bulletin in my back pocket so that if necessary, I can leverage that to push for a replacement.

[pmsteinm]

I had to top my coolant off a couple time since delivery so I complained about a possible leak. They tested fine of course, but today I noticed a huge mess because they overfilled the coolant while testing. I'm really annoyed that they don't know better than to not overfill. Makes me wonder about my oil change too.

I sucked the excess out (1 cup over so far) while it was still warm. In the morning when it's cool, I'll get it down below the max line. There was a mess under the hood and cap which I cleaned up and flushed a little water onto the injectors below.

Note that a cap leak is obvious because when you unscrew it there is a ton a white stuff like in the photos at the start of this thread. However, when it leaks all over the top the tank as a result it looks like the tank is leaking at the seam (the water seems to collect on the edge). I think when the tank fails it also leaks at the seam. So it can be hard to tell my looking if it is a cap leak or seam leak. If you clean everything up and there is white on the tank but the cap is clean after a while then you have a tank leak.



This is ridiculous:

[FJPM]

Do we know if the tank has been modified and if yes from what VIN?