e34 525i screech on startup

[Misue]

My 525i is making a loud screeching sound after starting the engine for a couple of seconds. It has the stock m50b25, and is an automatic. The noise seems to be coming from the back of the engine. I suspect it may have something to do with the starter bendix not fully disengaging so that the pinion still grinds on the flywheel, I am not sure. However the noise goes away once the car is fully warmed up.

[sixerguy]

Most likely culprit is a worn belt, use a spray bottle to wet the belt and pullys down and then start engine. Does the sound still occur? I'll agree, it doesn't sound quite like a belt issue, but I'd still rule that out before looking further.

[Misue]

You know it doesn't hurt to try that, so I will report back on what happens. Even though I am pretty sure it is not a belt issue, since I hear the sound from the back of the engine.

[Misue]

Yeah now I am positive it is not a belt issue
Same sound being produced.

[shogun]

get a mechanics stethoscope to find out the exact location of the noise, something like this https://www.harborfreight.com/mechanics-stethoscope-63691.html quote: The mechanic’s stethoscope makes it easy to identify piston slap, worn gears, faulty valves, water pump failure, damaged gaskets, defective bearings and other mysterious bumps and squeaks.

A long screwdriver or a metal pipe also helps, stick one end onto the parts to be checked and the other side onto your ear.

[Misue]

Right, I looked through the tools we have and it turns out i have an old one. I tested it and it is working. Now i need help to pinpoint where the noise is coming from exactly. I want to start with the starter since i think it is the source. As i understand the starter is somewhere under the intake manifold on the m50? Anyway thanks for the help.

[shogun]

"the starter is somewhere under the intake manifold on the m50?" yes
here is how to restore the solenoid on the Bosch starter https://www.youtube.com/watch?v=4x5xJmPNuks
use the forum search function for: E34 M50 Starter Replacement