[Knuppel]

Bought an E91 for the wife, and found brownish pink coolant in the expansion tank.

So I decided to do a coolant change, and whilst at it replace the auxiliary (electrical) water pump. It died, and had an error message in inpa. Now error message gone, but instead of pouring in 8 liters of coolant, it only took 6. (i unplugged the hose from thermostat to water pump also, so all the fluid was out).

Coolant bleeding procedure won’t start. If i power the pump with 12v, i can hear it run dry. There is no flow in the coolant tank. If i press the big hose going to the main pump, i can hear (some) fluid go through the aux pump for a few seconds, then it runs dry again. I’m guessing there is a blockage, maybe from the not so pretty coolant (though it wasn’t that bad), and probably the pump was left dead for some time.

Now for the questions:
- not having flow in the expansion tank (whilst car runs), is this normal?
- can the aux pump hurt my car, now that it sucks out coolant, but no coolant flows back?
- are there any valves that should open before the aux pump can run? (maybe it’s not a blockage but i’m not supposed to run the pump manually and there is a big air pocket somewhere?

Help me please because my wife needs the car on monday otherwise i’m in a world of hurt... (‘you should have never!’, etc)

[NinetyEight740]

Are you just running the car or doing the coolant bleeding procedure? You need to do the bleed procedure if you’ve drained any coolant or you’ll never get the bubbles out.

[Knuppel]

Originally Posted by NinetyEight740

Are you just running the car or doing the coolant bleeding procedure? You need to do the bleed procedure if you’ve drained any coolant or you’ll never get the bubbles out.

I did the bleeding procedure. But apparently on the N46 engine (2.0l), there is no electric water pump. I followed the instructions in ISTA. Fill it with bleeder screws open, then idle the car for 1 min with fan on low and temp on highest. Drove the car today coolant temp is max 105 celsius. Coolant did not drop. Seems good.

But it’s still strange that there is no water running through the auxiliary pump. If i power it manually (car off), i can hear some water seeping through, but it’s very little. I’m worried there might be a blockage in the heater core because the previous pump died and was never replaced. The new pump now gets hot probably because it’s running dry.