Planning on doing this over the weekend and came across an interesting bit on Wikipedia regarding the M42:
"The second problem is far more significant - the upper oil pan casting incorporates the oil pump's supply passage, and is sealed to the crankcase oil filter housing with a paper gasket. Thermal cycles and engine vibration tend to loosen the six 10mm upper pan mounting bolts inside the motor.[5] Routinely, a loose 10mm bolt or two can be found rattling around high-mileage M42 sumps. If not caught in time, the paper gasket sealing the oil pickup passage can be forced into the crankcase by oil pressure, potentially causing a major loss of oil pressure and/or aeration of the motor oil. Thus it is strongly recommended that any new owner of an early M42 remove the lower pan to inspect these bolts. A permanent solution is to remove & clean the six internal 10mm bolts, apply a thread-locking sealant to the bolts, and re-assemble."
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https://en.wikipedia.org/wiki/BMW_M42 The last bit really caught my eye...could this be a way to prevent future leaks by applying the threadlocker? Mine is 200K+ miles so I'm imagining this is the last time I do this job realistically - anybody ever tried that?