At ~2800 RPM, a very loud grinding, screeching, whining noise will start. The noise will continue at any RPM, until the engine is restarted.
The issue started suddenly while driving a few weeks ago. The car is idling a little rough, and has a lack of power.
No SES, but scanner showed pending P0328 (knock sensor). Lots of INPA error codes, but they all seem to be old/unrelated...
2EA1
2E68
2E69
2D06
A36B
A0B2
A670
A554
A3B2
E194
E18D
9CAC
9CD2
E58D
So far, I've replaced knock sensors, DISA valves (bigger one was broken), cleaned Vanos solenoids. My next guess is something to do with valve cover, perhaps valvetronic motor or eccentric sensor. The lack of error codes/hints, is what is keeping me from randomly throwing more money at it.
This is now the strangest BMW/car issue I've ever experienced. I've spent hours searching forums/youtube for similar symptoms. Any help would be greatly appreciated. All my mechanics/friends are scratching their heads... which usually means there is something obvious we're overlooking.
WAG. VANOS related.
04M3 TiAg 69k slick-top 3 pedal
99M3 Cosmos 61k S50B32 euro 6Spd
88M3 AW 43k miles Project FS
WTB: 3.5" Eurosport/Conforti CAI
sounds like an idler pulley bearing
It definitely does sound like some kind of pulley and/or bearing. However, I’ve run it with drive belt removed and still has the issue. I replaced VANOS solenoids, but not too familiar with the VANOS system on the N52, so idk what else to look at.
I’ve reset errors in INPA and only got back 9CD2 (for mirror malfunction lol). I have nothing but the sounds and symptoms to go on. I’m starting to rule out anything sensor or electrical. The sound is really hard to judge. It’s a metallic whirling rattle. Perhaps it’s just something internal (blown motor).
But, it’s much more profound from under the car. I’m wondering if it’s something down the drivetrain. Clutch, flywheel, exhaust, etc...
Im honestly getting close to pulling the plug and selling for parts. Really lost.
I took the belt off, ran the car, and the issue remained. This rules out any belt drive accessories or pulleys, correct? I was thinking Alternator bearing or AC compressor.
What really confuses me is how the issue it activated by revving. The noise is not present when car is started, it is only when revved to a certain RPM range. WTF is that about!?!?!
Update. I ended up selling the car as is. However, after doing some in depth inspections with several mechanics we are 98% sure that the issue was the flywheel and/or clutch.
I was going to sell the car anyways, so just took the hit and sold it with the issue. Thanks to everyone for input.
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