My water pump recently went. 2 days before I need to take a 2300 mile road trip I started the vehicle and heard a slight knocking that was not normal. Figured it might have been an idler pulley bearing, but decided to by a water pump and pulley as well.
Chanced it and drove the 2300 miles, things got worse over the trip but luckily held together.
Easy thing to do, pull belts, then rotate pump and pulleys, the problem will be obvious once you have the belts off.
Seems that the pump seal starts to seep and will then contaminate the pump bearing and then the bearing cage breaks and the pump can get very noisy. At least this is what happened in my case and around 78k miles on my 2008 a in August.
Suggest the following.
Replace pump and pump pulley. The pulley is plastic and may be rusted on the pump, not worth chancing it for the $15-$20 IMHO.
I was able to remove the pump without removing the crank pulley, but if you have big hands and are not very patient, then remove the crank pulley.
Suggest installing a
Bimmer Fix | Coolant Pipe Repair System coolant stent while the pump is out. Well worth the extra time and money IMHO.
Also suggest a Hamburg Tech 90C thermostat. Have been running one in my car for almost a year. Did get an error for the engine temp once, but the stat became soft in under a year and warranted the stat via ECS Tuning.