The oil pump nut on my 99 e36 m3 backed off completely at 61k miles, resulting in complete oil pressure loss. The dealer would not cover it under my CPO warranty. I replaced the oil pump nut myself. I highly, highly recommend a helper - even better if they've done the job before. There are most likely shortcuts here and there that I missed, but this documents how I successfully completed the project.
Tools and supplies:
Assorted wrenches and sockets including a universal joint and different length extensions - air tools help
Engine hoist, or some other way to support the engine without getting in the way of the oil pan
Jackstands or a lift
Oil drainpan and new oil
New oil pan gasket and gasket sealant
Loctite red #272 hi-temp (I used standard loctite red because I couldn't find 272 hi-temp)
Safety wire and compatible nut. I got mine from Chuck Stickley at www.cssmotorsports.com (http://www.cssmotorsports.com/) You can also use a punch to deform the pump shaft threads.
Someone to help!
Latex gloves and shop towels

Read through all of these before starting!

http://m3.digital7.com/oilpumpnut2.jpg
http://m3.digital7.com/oilpumpnut.jpg

1. Get the car up in the air. I'll assume since you're tackling this job that you can safely accomplish this. You need enough room to work, but not so much that you can't hoist the engine. I had about 2 feet from floor to car using a lift.
2. Drain your oil. Let it drain for a while, since whatever you don't get out now will probably end up in your hair.
3. Remove front sway bar bushing brackets - two nuts per side. Swing swaybar out of the way. Also remove x-brace if equipped.
4. Remove main serpentine belt. We will be removing the power steering pump later, so you can just let the belt hang loose for now.
5. Remove engine mount nuts. They can be seen through a hole in each front lower control arm. See diagram circle 2.
6. Support the engine with your engine hoist. There is a bracket for this purpose in the very front of the engine, on the top.
7. Remove the two clamps that hold your steering shafts together. Turning the steering wheel can make them more accessible. See diagram circle 3.
8. Remove the front subframe bolts. Air tools help immensely with this. You will need to utilise that universal joint to access them. There are two per side. See diagram circle 4.
9. Remove the lower control arm bushing bolts. 2 per side. If you are on a lift, and the wheels are on the ground, chock them! Otherwise, they will roll right into your front bumper. Ask me how I know! See diagram circle 1.
10. Pull the subframe down, it should move about 4". You may need to hoist the engine up slightly to access the oil pan.
11. Remove the 3 mounting bolts holding the power steering pump on. 2 bolts are at the top, and one is below. The bottom bolt screws into the oil pan.
12. Remove all oil pan bolts, there are a lot of them. Again, your universal joint and extensions will help greatly. 3 or so go through the transmission's bellhousing. You must also remove the 3 trans mounting bolts that thread into the oil pan with a female torx socket (Thanks, Jim B!). I used an 8(?)mm socket to remove/replace these due to lack of female torx sockets, but it can't be a good idea.
13. Don't forget- if you want to check the looseness of your oil pump nut - IT IS REVERSE THREADED!
14. If the pan does not fall loose, double check that you've removed all bolts. If it still won't budge, I'd use a soft mallet or a block of wood to knock it loose.
15. I had to finagle my pan out. I ended up pulling down the rear part of the pan first, and then maneuvering around the oil pump gear. You'll see what I mean when you start to try.
16. Once you have the pan off, check to see if your pump nut is loose. REMEMBER it is reverse threaded. Spin it counter clockwise to see if it is tight or not.
17. At this point you can either be happy your nut has not come loose, or glad you took the time to check. Choose your rationalization based on your findings.
18. Either way, remove the nut. It's reverse threaded, dummy. Spin it clockwise to remove. If you accidentally pull the gear off the pump, you might need to use a standard screwdriver to turn the pump shaft so it lines back up with the gear. My nut backed off completely so I had to do this!
19. Clean the pump shaft of oil. Apply loctite red and torque the nut down. I torqued hard with a 3/8" ratchet. Apply your insurance policy - either safety wire the nut, or punch the threads. You do not want this nut to come off! I did not feel safe just using loctite. I know mine isn't going anywhere.
20. Time to put everything back together. If you choose to, remove the old gasket, and install the new one with gasket sealant. Put the pan back on. Make sure the dipstick tube is seated properly. Use a new o-ring if necessary. Torque the oil pan bolts back on. Torque trans bolts back on.
21. Reinstall power steering pump.
22. Loosely reinstall front subframe, starting with the 2 subframe bolts on each side. Gradually tighten them until you can ease the steering shaft into the coupler. Make sure your steering wheel and front wheels are STRAIGHT before you do this! Once the shaft is started into the coupler, slide it so it is even on each shaft. You may need to pry with a screwdriver to do this.
23. Start the lower control arm bushing bolts. You may need a helper to move the front wheels back and forth to get them lined up.
24. Once everything is started, torque subframe and control arm bushing bolts to spec.
25. Reinstall swaybar brackets.
26. Lower engine slowly. It should fall right back into place. Reinstall engine mount nuts and torque to spec.
27. Fill engine with oil and start it up!
28. Enjoy newfound sense of accomplishment and security. My dealer wanted $800 for this job!

How did your car react when this happened to you? Here is what happened with my car, driving as normal, around 40 mph and red oil pressure light came on. Stopped car, checked oil, all fine but light still on. Car is parked and I am assuming your problem is what happened. Do you think there is anything else going on? Also how much did you have to hoist the engine to clear the oil pump gear? I'm not really looking forward to dropping the pan, seems like a big job.

Same deal, oil light came on and I turned it off. Oil levels were fine. It only needed to be hoisted a few inches if I remember correctly.

It is s pain, but much easier with a helper!

Good luck,

Chris

I'll be pissed if this happens to mine. I am way too lazy to do this right now.

Fuck that noise. S54 swap FTW.

some progress. Can't get the universal joint off the steering column...what's the secret???

Found the trick, use a bigger hammer, I just had a heck of a time getting the steering shaft off so I could lower the front end. Everything else went along very smoothly until I had to break for valentine's dinner. Only have the last 3 WORST oil pan nuts to reach on the back top by the bell housing. Not fun. For my hoist its working perfect. I used a 4X4 post and cross beam and a transmission jack to raise and support the engine. Just a simple HEAVY duty chain I had sitting around doubled up over the 4x4 with a huge "eye screw" just to guide the chain and prevent any movement of the chain (like where would it be going?) I hope to have the oil pan off by tomorrow...and see that the nut was my problem...or some other realtively easy fix.

Congrats on the progress! Keep us updated.

Chris

Pan dropped...damn nut. Pan back on, just need to put everything back together now. FYI, had problem with the two hidden nuts WAY up in the bellhousing and need to get 2 new motor mounts. Anyone starting this be sure to undo both the top and bottom of the mounts. Oh well, if that's the worst not bad. Hopefully tomorrow I'll have it up and running.

After feeling exceptionally accomplished by completing the oil nut secure procedure on my 98 M3 (yep the nut was in the bottom of the pan). I was excited to start her back up. Problem is all dashboard lights came on like normal but no crank (could hear what I assume was the fuel pump pressurizing). Battery is great, charged full, all accessories work. I have carsoft so read the codes and I got 235 and 236 "Heat Output OX sensors" errors but assume that is just because the engine is not running. The one that I think is the problem is "EWS Key Transponder in Key...Key not recognized". The car was working perfectly fine, except for the zero oil pressure which prompted the job in the first place. Any ideas on what to do? What should I check? Because I only had one key when I bought this car I just got back from the dealer and ordered a second key because of the above error but the tech at the dealer wasn't overly confident that the key went bad (and seems too much of a coincidence the key would have gone bad). Might I have knocked off some plug or with the battery dead and unplugged for about a week could the key or car need some type of programming? My son had the ignition turned on for about a week so the battery went COMPLETLY dead. The key does not have any buttons on it other than one to turn on a little light. HELP!:confused:

Here were the error codes from DME and WDS- I see the Code Index is different, does this indicate a synch issue?

Single diagnosis DME / DDE - Status: ERROR ! ______ _____" Module Info : DME / DDE ______ _____
DME MS41.0 ______ ____!
BMW Part Nr. : 1406464 !
Hardware Nr. :_ 02 ____!
Software Nr. :_ 12 ____!
Diagnose index:_ 21 ____!
Code index :_ 01 ____!
Bus index :_ 10 ____!
Production Date: 41/97 _____ ______ _
DME41_FE.DXT
_____ _____.
236 Heat output : oxygen sensor Bank 2______ _____
1 At cylinder 4-6; after catalytic converter______
- oxygen sensor heating_____$
- cables to the oxygen sensor_____,
- Final stage of the DME control unit______ ______ ______ ______ ______ ______ _____0

250 Tank venting valve : Function fault ______ ______ ______ ______ ______ ______ _____.
235 Heat output : oxygen sensor Bank 1______ _____
1 At cylinder 1-3; after catalytic converter_____!
Open or short circuit at :______
- oxygen sensor heating_____$
- cables to the oxygen sensor_____,
- Final stage of the DME control unit______ ______ ______ ______ ______ ______ ______ - Single diagnosis completed !_____M___________________________________________ ________________________________________ _____

P Single diagnosis EWS - Status: ERROR ! ______ _____" Module Info : EWS ______ _____" Supplier : _UTA ____!
Device Nr. :4 146 048 ____!
Hardware Nr. :_ 2 ____!
Software Nr. :_ 2____!
Diagnose index:_ 1 ____!
Code index :_ 2 ____!
Bus index :_ FF ____!
Production Date: 41/97 _____ ______ _
ews_feh.dxt: _____ ______

01 Key 1 not recognised______ _____9
Key recognising procedure during the start process : ______ _____D - The transponder in the key is supplied true the ring antenna. _____4 En sends the key data to the EWS control unit._____@
- The EWS control unit controls the data, and then sends the_____< permission signal to the engine control unit (DME/DDE)______ en de starter._____=
- After starting the EWS control unit calculates new data_____G (changing code) and the sends it to the transponder into the key.______ ______ ______ ______ ______
- Single diagnosis completed

Now that the battery is charged again, have you tried disconnecting the ground for a minute to reset the computers?

Also, have you double checked to make sure no electrical connections were left disconnected? Something like the crank position sensor being disconnected would cause a no-start issue.

Chris

Disconnected battery and fully charged then hooked back up. Also tried new dealer key and no luck. Dropped it off at Zygmunth to see if they can figure it out. I hope I knocked some wire loose and that's the issue, would seem the most logical but where I was working I checked all the plugs and they seem secure. Also reviewed the fuses and didn't see any burned out. Everything except for actually cranking and starting looked and sounded normal (all lights and pressure up) but no click or anything from the starter. That's why it seems like something is telling it not to crank (imobilizer?). Have no idea about a switch that was installed by someone in the passenger foot well under the glove box, looks like a kill switch. I will let you know what I hear once they work out the issue. Tried to pop start it as well but not even close to firing up. Something funky....

That's too bad that you made it that far and it wouldn't start. You dropped it at Zygmunt in Doylestown? Where are you located?

Chris

just around the corner from you. In furlong off York Rd.

Zygy just called and said it's aftermarket alarm related...and dealer never gave me the key fob to deactivate it. All else checks out perfect on his computer scan! Argh

Retract that, got another call. Problem solved. And I have myself to blame. While doing the job the right motor mount completely broke and could not remove it. Had to take off the entire arm, disconnect the ground and take it to a garage to have them take off the nut and broken mount. When I put it back in I apparently broke the ground. He just redid it and the car fired right up. Guess on the positive side he scoped it on his new BMW machine and everything checks out perfect. Don't have the final bill but bet it's cheaper than had I had him fix the oil pump nut. Guess it's a small victory...

Congrats! I'd bet his rate should be pretty reasonable.

Chris