[JayPixelF33]

I was digging around the engine bay today so far no codes and coolant reservoir is full. however see attached photos seems like a small rubber coolant hose that goes into the engine is causing a slow leak.

anyone have any experience with this? should I just change the small hose and add a second ring clamp?

all other hoses appear intact including the infamous plastic reservoir hose.

2018 430i convertible 80k miles

[JayPixelF33]

Looking at real oem seems like this is the turbo coolant return and the rubber part doesn't seem to be sold separately.

https://www.ecstuning.com/b-genuine-...c/11537643226/

[JayPixelF33]

After checking the coolant reservoir it seemed to be overfilled, I extracted some coolant to get it down to the MAX fill line and left the cap off for about 10 min with the engine on to release possible air in the system. (if I end of replacing the line I will do a coolant full coolant flush).

Also looking at the service records the coolant lines (the reservoir line that is a common failure point) was replaced at 80k miles (currently has 84K) so that line seems good for now


I will monitor and see what happens next time I take it out.

[JayPixelF33]

Finally got around to fixing this
$89 for the turbo coolant return line

Have to remove the air box and part of air intake to access torx bolt that holds the line
Also need to remove the lower line to remove this got stuck on this part for a min thinking I needed more brut strengthen
After a week and a half no leaks!

[ReiChr]

89 $ pretty expensive for just a rubber line... But good for you, that your problem is solved!

[JayPixelF33]

Yeah it is. It’s a strange design with rubber hose connecting into a rigid line so you have to replace the entire thing good old German engineering