Noamit

Quick update: 120kms later, the temp needle stayed right in the middle with no movement. Coolant level is stable. I think I can call it a success! I learned a lot here. Thanks everyone, this wouldn't have been possible without this space and people

This did cross my mind, which is why I bought new belts. I inspected the old belts and the conditions weren't too bad, so I kept them in case I needed it. Glad I did. The new AC belt was incorrect. To Vass' point, I needed one with an extra spline. I put the old belt back in and the sound is gone. Pulleys aren't exactly mint so I think I will replace them soon too. The corrosion was quite nasty, so I will be putting fresh coolant in soon, but I think I'm going to disassemble the system again in a few weeks to check the AC and thermostat holes and see if they're clean. I've had the car for a few months and it always had a whiny AC too. Looks like I will be replacing a bunch of spinny things in the near future. Thanks to all of you who came to help! I've yet to do a proper test drive so it's not quite over, but idling is perfect. Will be back soon when something else inevitably breaks.

I'll also add there was one day between me doing the two flushes yesterday evening and using a cleaner this evening.

So I installed new belts, new pump, cleaned the area as much as I could, then flushed the system twice with distilled water. I then used a Penrite radiator cleaner before putting antifreeze in, and it started making this noise... Bad pulley? Turning AC off doesn't stop it. It took about 30 seconds after starting for the sound to begin the first time. I've stopped and started the engine again, and that time the sound immediately came back VID20240930200418.mp4

Honestly, things are looking pretty gross in here. What would be the best way to clean this so the new pump can be installed without damaging the o-ring?

Update: I don't think water pumps are supposed to look like this.

Right, this might be the culprit for the leak too then. Judging from the mess I suspected it might be coming from the top of the engine. Good to know that water causes staining! I realised there's a leak when I was on the road and the engine temp started rising. All I had was water which was enough to get me home.

Thank you! Time to pour more money into this bottomless pit.

Hi everyone, first time poster and a mechanic-wannabie here. TL;DR M54B30, took the belts off and found the water pump pulley to be wobbly. My E39 530i recently developed a pretty serious leak, but I wasn't sure exactly where it was coming from. The front end of the engine is quite dirty, and since I've never even inspected the belts I thought this'd be a good excuse to take the fan, shroud and belts off so I know how to do it, clean the area, put everything back and see where the leak is coming from. After taking the belts off, I noticed the water pump pulley has a lot of play. Is this normal, and if it isn't, what should I do? Thanks in advance VID_20240916182736.mp4