So I’ve been chasing a cooling issue on my 2008 we 135i. I originally thought it was the water pump because when I did the bmw water pump test there was no stream coming from the reservoir. I switched the water pump out, still nothing, then I switched out my thermostat and still nothing, and most recently I switched out the buss fuse In the power distribution box on top of the battery because that had been the reason on my old 335i but still not working, I’ve got no idea what to do next and any thoughts or advice would be greatly appreciated.

Morning Joseph

Welcome to the Forum

I would get a diagnostic scan done by someone with BMW capable software or if you want to trace it yourself I would begin at the pump. Check the connector and loom for continuity, is the water pump relay operating, you say the fuses are OK it may be worth using a good quality contact cleaner on all connectors and fuses. Is the pump you changed actually working ? Was it new or a replacement ?

Good luck with tracing the issue

Dave