2016 750li coolant low no leaks

[77777]

Hello 2016 750li 80k km. I got a coolant low message looked inside the tank and the coolant wasnt visible at all not a drop. Filled it and the next day got the same message and the same situation inside the tank. There are no leaks that I can find. Please tell me its not the gasket. And if it is whats the damage to my pocket?

[Caveno]

Common theme on these cars. Just add coolant. I top mine off every so often. Make sure you use the European coolant version not the green stuff. Nothing to worry about

[Qsilver7]

Since there's a low temp & high temp coolant reservoir...you didn't mention which one you are working with. Can you verify if you are checking and filling the low or high temp reservoir? Thanks.

[Qsilver7]

Originally Posted by Caveno

Common theme on these cars. Just add coolant. I top mine off every so often. Make sure you use the European coolant version not the green stuff. Nothing to worry about

Just an FYI...BMW has been using GREEN coolant since around the 2019 model year.

BMW changed from the old blue (G48) coolant to a green (HT12) coolant. And for a while they were using a magenta colored HT12 coolant.

Fortunately, the G48 & HT12 coolants are compatible. If you can't find or get the BMW brand...look for G48 (blue) or an HT12 (green or magenta) coolant. I know XEREX sells a G48 coolant...and I've seen aftermarket HT12...but cant remember the name brand.

Just thought I'd bring it up in case an owners opens their coolant reservoir and sees green coolant...there's no need to freak out...it would be correct especially if the car is a 2018-up.

[77777]

Originally Posted by Qsilver7

Since there's a low temp & high temp coolant reservoir...you didn't mention which one you are working with. Can you verify if you are checking and filling the low or high temp reservoir? Thanks.

Thanks for helping. Its the high temp reservoir, the one on the driver's side, that has been getting empty. Also after refilling and driving for 5 mins after that the car was parked overnight and morning got the same message. So the coolant went somewhere while the car was parked the whole night.

[Raimo5]

This "high temperature" loop is for engine and turbo cooling. If you lose a tank of coolant a day and it ends up in combustion chamber, then you should have massive plumes of white smoke coming out of your tailpipes. If it leaks in the turbo, on the turbine side, then you might not see meaningful increase in tailpipe emissions.

Is oil clean, no coolant mixing? Also, are you sure the leak isn't external? All that carpeted underbody paneling might hide even moderate spills.

[77777]

Originally Posted by Raimo5

This "high temperature" loop is for engine and turbo cooling. If you lose a tank of coolant a day and it ends up in combustion chamber, then you should have massive plumes of white smoke coming out of your tailpipes. If it leaks in the turbo, on the turbine side, then you might not see meaningful increase in tailpipe emissions.

Is oil clean, no coolant mixing? Also, are you sure the leak isn't external? All that carpeted underbody paneling might hide even moderate spills.

How likely is it that a stationary parked car would leak into the combustion chamber or the turbine? Reason im asking is where Im from the dealership is notorious for exaggerating minor issues and charging as if its a major one. I want tk bring it in and be as prepared as possible.

[Raimo5]

Originally Posted by 77777

How likely is it that a stationary parked car would leak into the combustion chamber or the turbine?

Very unlikely. If it ends up in combustion chamber, then at best you would have very rough crank with loads of white smoke coming from tailpipes. At worst, you would hydrolock the engine and possibly damage the conrods.

Should this amount of fluid be dumped into a turbine side, then you should see fluid spewing out from tailpipes.

As coolant loops are pressurized, then I rather think you have a leak when car is being operated. Why it gives error after it has sat overnight, is because coolant has cooled down and shrunk in volume, thus falling below the minimum threshold. This is of course only an educated guess based on a mode of failure and rapid progression of fluid loss. Internal leaks tend to develop slowly. Also, I take that you have not noticed any coolant and oil mixing in their respective loops.

There are loads of hoses and connections that reside near hot bodies in engine bay that are capable of evaporating the leaks before anything reaches the surface of parking area. So do not disregard the possibility of external leak, especially in absence of evidence that supports internal leaks.

If local dealer networks are unreliable and say that you need head gasket or what not, then I would like to see coolant loop CO2 measuring test results. If you have internal leak in that loop, then engine operating pressures will pressurize the loop and CO2 will enter it, making it detectable with appropriate measuring equipment.

[77777]

Thanks for helping me theres only 1 dealer here and they are straight up thieves

[77777]

Alright I brought it in and the issue was a broken top cover which then caused one of the hoses to basically blow out with a pretty decent cut. Replaced both the hose and the cover.

[Qsilver7]

Great...thanks for the update...glad you got the issue resolved.