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M20 Oilpan Gasket - things the Bentley Manual doesn't tell you, part bazillion!

Discussion in 'E30 (1984-1993)' started by MGarrison, Oct 2, 2014.

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    MGarrison

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    The Bentley Manual is very good - however, sometimes it just doesn't cover every detail that's really helpful...

    If you're going to drop your oil pan in your M20-engine'd E30 to replace a leaking oil pan gasket... the Bentley procedure is fine for removal - their procedure requires removing the oil-pump to get the pan out. However, putting it back the same way, it can be a time-consuming trial-&-error to absolutely ensure the oil pump driveshaft is in place, as it's about impossible to see the positioning hole for the top end of the shaft, you can't see the lower hole for it that's on the pump, and with only the engine jacked up as far as it can go (which takes removing the motor & transmission mounts), there's limited space to get one hand in there feeling & fumbling around pump driveshaft, while trying to hold the oil pump in place. Also, there's not enough room to get a torque-wrench in and onto the oil-pump mounting bolts to ensure they're torqued properly. Jacking the engine up as far as possible, removing the steering rack bolts, and pulling the rack out of the way, keeping the subframe bolted up, does give enough clearance to remove the pan without having to remove anything off the front of the engine.

    You can remove the oil pan & reinstall it without removing the pump, but to get enough clearance for that, it takes dropping the front subframe (obviously, you have to support the motor - I put a safety stand on the a/c bracket), and that can all be done fairly easily. However, the downside to that approach is getting the subframe back up and in place - for me, the subframe dropped down & forward, and getting it back up and properly positioned took forever, lots of fighting it & trying multiple things to make it work. Be careful if jockeying things about not to jack the front end of the car off the jack stands, or front lift supports if you're using a lift. I opted to put some gasket compound on the suggested areas before putting the oil pan up close to the engine.

    Having not tackled this task before, I couldn't anticipate what a hassle getting the subframe back into place would be - next time, one idea may be to obtain some threaded rod that match the threading on the subframe bolts, or getting some really long same size bolts if that's possible, plus appropriate nuts and some beefy washers, and replace each bolt, one at a time, with the longer bolt or threaded rod w/ nuts & washers, and once the stock bolts are replaced, then let the jack down and lower the subframe so it's suspended on the bolts or rods, & they could then be a guide for getting the subframe back into place.

    Whether you remove the oil pump or not, it's probably not a bad idea to clean the screen over the oil pump intake, note the screen is not flat, make sure the concave/convex orientation is the same going back as it was before removal.

    The Bentley manual doesn't mention the ground wire, but on mine ('87 325is), it needs to be detached from the oil pan. Also, the sensor harness connector on mine is completely different than that shown in the Bentley - presumably early M20's have a round 2-pole connector as mine does, versus the rectangular 3-pole pictured in the Bentley manual. If you're going to do this project, plan plenty of time, this took me waaaay longer than I figured it would!

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