Small Coolant Leak - Help

[Johnr32]

I need some help with the z again, there seems to be a small leak coming from around the area highlighted in red below:
Anybody have any idea what it is? the expansion tank looks ok but it was quite hard to tell without removing it. From what I saw it comes from the area circled in red and drips down to that light blue coloured screw.

 

[G600]

If that's the part I think it is then it removes from the expansion tank by twisting, a bayonet type fitting, there's an o ring in there that may be the source of the leak.

 

[Johnr32]

Does bmw sell the o ring separately?

 

[stupot67]

Does bmw sell the o ring separately?

I don't believe they do, but if your willing to wait a day or 2 and PM your address, I think I have some Viton O rings the correct size, I'll send you one in the post.

Stu.

 

[Z4Lithuania]

Hello,

I have a small coolant leak too. Previous owner tried to seal it with some kind of sealant, but it doesn't help as I can see.

Leak is comming from this area (picture below), is that some kind of radiator drain plug? I can't see anything because of that sealant, so maybe you can help me to figure it out? What should it be in that area?

Thanks in advance!

 

[Johnr32]

Hi Z4Lithuania, my problem turned out to be a tiny hairline crack on the expansion tank, it was only visible when it was taken off for inspection.

 

[Z4Lithuania]

Hello,

Please, can anyone describe for a newbie, how this radiator / expansion tank mounting plate system works?
Here is a link of a part I'm talking about: https://www.ecstuning.com/b-genuine-bmw-parts/spacer/17112248408/

There is like 20mm diameter plastic tube on that plastic bracket (you can see it in 4th picture), that goes to coolant radiator. But where does it go next? As you can see there is a hole through it, what part am I missing here?