[Ed CT]

On my 2018 440i, I found the source of a coolant leak that I was looking for, but cannot ID the Coolant Hose that is connected to the Oil Filter Housing (this hose's connector at the OFH is where it’s leaking).

In the pic, the blue arrows point to the hose coming off of the OFH and it goes toward the firewall. The hose with yellow-highlighted connectors goes from the radiator hose to (I think) the Aux Electr Water Pump under the Intake Manifold.

I discovered here that the PO replaced the plastic OFH with an Aluminum unit (a good thing). But did he actually mix up these two coolant hose’s connectors at re-assembly?!?

I am thinking that the blue arrow hose should connect to the radiator hose at left, and the yellow highlighted hose is actually p/n 11538611277 and should connect the OFH with the Aux Electr Water Pump.

Any help with verifying my thoughts here is appreciated.

EDIT: an excrutiating search on RealOEM had no diagrams that show the yellow highlighted hose p/n 11538611277 connected to the OFH - it only shows it connected to the Aux Electr Water Pump

[Ed CT]

Found a couple of OFH replacement videos, and it appears that the shorter yellow highlighted hose p/n 11538611277 was re-assembled wrong. It should go from the Aux Water Pump to the OFH. The blue arrow hose should connect to the radiator hose at left, not to the OFH.

This is a big relief, because I had resigned myself to having to R&R a leaking OFH, plus the plastic flange while I was in there.

Now I'm wondering, with these two coolant hoses mis-assembled, what was it doing to the heating system? lol I haven't driven the car enough to notice any issues.