[Kripster]

My coolant indicator came on again so had a dealer check it (2nd time for this car). He said backup was a little low so he topped up. Main he said was fine (opened slowly and as it was hot the sound it made confirmed to him it was fine). Light cleared but came on again this evening. It's almost as if cold weather triggers the indicator. Is it a malfunction? Anyone else having the issue?

[AP]

There is a thread on this, seems quite a few of us have had faults causing coolant loos , myself included.

The coolant shouldn't disappear so don't be brushed off by the dealership as there is bound to be an underlying issue that needs to be resolved.

In my case it was the reservoirs that were at fault and fixed under warranty.

[Kripster]

Originally Posted by AP

There is a thread on this, seems quite a few of us have had faults causing coolant loos , myself included.

The coolant shouldn't disappear so don't be brushed off by the dealership as there is bound to be an underlying issue that needs to be resolved.

In my case it was the reservoirs that were at fault and fixed under warranty.

Ok. Did they say what was wrong with the reservoirs? Did they replace them?

[AP]

In my case the reservoirs were leaking (don't know more than that). They pointed out that if you look down in the metal work below there are the remains of some residue which was the clue.

They replaced them both(there are 2) under warranty.

Whether that the same issue with yours or whether its something else, it shouldn't happen so the dealer does need to fix the issue . They can do a pressure test to see where the leak might be coming from.

As I say there is a thread on this forum which has quite a few pages of people here with this symptom.

[b74heavy]

I have been checking my coolant reservoirs. The dealer has run a pressure check and found no leaks. I said the fluid is going somewhere. I have looked at the medal work under the reservoirs and cannot see any leaks. I also have checked all the piping and hoses I can see and I cannot see any evidence of a leak. Don't know what to do at this point. I have 23,000 miles on my 2019 540i. I am thinking of taking it to a local mechanic and have them look for the leak. When I had a 2003 M3 that had the connecting rod bearings changed this mechanic was doing an oil change and found a rear main seal that was leaking. Got that fixed before the warranty was over at the dealership. I need them to take off the cover under the car. I'm sure the leak is small but I need to get it fixed. It shouldn't leak at all. The dealer is telling me it runs hot. I had a good laugh at that one.

[clee1982]

when I took my dealer for oil change I asked them to do a whole day pressure test, they finally admit they see a tiny bit pressure drop and are currently still investigating...