A few days ago I started the car and noticed sort of a "slapping" sound. It didn't sound normal but after a minute or so it went away.
Car drove perfect for the next couple days.
This morning when I started it, I noticed that the steering wheel was juddering when turning the wheel at idle pulling slowly out of the garage. Going toward full lock, I heard a couple clanks and it was apparent something wasn't right.
Issue seemed to go away, and then after leaving for lunch I noticed that the steering wheel kept juddering when turning past one rotation at very low RPM.
I called my tech/friend at South Bay BMW and explained the situation to him. He said that he sounded either like a steering rack or a power steering pump. I asked him if he ever replaced a rack on an M3 before, and he replied that he'd only replaced them on non-M e9x's before.
He said to check the fluid and make sure that it wasn't frothy.
A couple minutes later into the conversation he said "Wait! You have a power pulley right?" I replied that I did. He then said that he's seen the belts go a little bit more frequently on the power pulley kits because of having to stretch the belt over the tensioner. Not sure if that's accurate or not, but reading further you'll find he was spot on about the belt.
Issue seemed to get slightly worse. Went back home and looked in the engine bay with my iPhone flashlight, and saw what appeared to look like frayed wires down by the bottom of the radiator. Upon closer inspection, it was obvious that the belt had seen much better days. There were pieces of it all around, and I could see small chunks missing from it. Thankfully had nothing to do with wiring!
Drove to dinner and didn't really experience the issue. After dinner I started it and heard a "knocking" type noise that was incredibly loud. Opened the hood and took a video for you guys to hear, and then closed it and took another one. Within a mile of driving the noises stopped.
I called the US head of RDSport (tuned a few cars for him) and asked him if he had the belts. He replied that he would order them in the morning. So provided that I can make it to OC (about 45 miles) without the belt snapping tomorrow, I think I'll be in good shape. Given how backed up I am, this was horrible timing! Damn you M3.
I'm also going to have the power steering fluid changed. It didn't smell too good and had never been replaced before. The car has been tracked many times and the pulley was installed when the car had about 3,000 miles or so, so it's had this belt and fluid for about 44K miles and multiple track events. Going to change the coolant tomorrow too since that and the power steering fluid are considered 'lifetime' fluid by BMW...
Will report back and let you know if the belts + fluids fixes the issue. Other than the steering judder at low speeds while turning, the car drives perfect and has zero issues.
If any of you experience this noise or steering judder, check your belts! I would say that belts should be replaced between 40K and 60K miles, so this seems right on the money!
And with hood closed
PS: I wonder if somethings wrong with the tensioner...? I guess I'll find out. Hate dealing with warranty.