i did the job from above and below. I jacked the car up a little bit so I wouldn't bend my band as far as usual to work in the engine bay and so I can lay under the car as well.

I removed the oil filter and looked around for the 5mm allen. I only saw one 5mm allen back there so I assumed it was for the crank sensor. Bolt was fairly dirty so i cleaned it out a bit before turning the wrench and stripping it entirely. I had to use a long 3/8''s extension to a u-joint in order to reach it in a W201 engine bay.

after undoing the bolt, I pulled the sensor out, undid the two clips under the intake manifold where the wire runs through and pulled it out from the front of the engine bay.

routing it under the intake was kinda tricky. I shoved it as far as I could under the intake manifold from above and then I laid on my back under the car to route it properly to the general area where the oil filter was at. then plugged it in from top and bolted it back in.