DIY - Oil pan (sump) gasket replacement
Been a long time reader, but a first time poster on these forums.
About a week ago I finished changing the oil pan gasket on my 2000 320Ci (with manual transmission). Before starting the job, I spent a while trawling these forums / Google / YouTube, but couldn't find a detailed DIY. There were fragments of info everywhere, but no start-to-finish instructions. So this is going to be my first attempt at a DIY.
I know that there's a popular quick & easy procedure out there where you can replace the oil pan gasket by cutting it in two places. By no means am I going to try to challenge the merits of that particular procedure. However, for those of you who want total peace of mind (like me), this is the "kosher" way of changing the oil pan gasket.
When you do a search on replacing the oil pan gasket on the E46, the most common theme is that this job is pretty high on the PITA scale. Having now completed the job, I'm certainly not going to dispute that statement! The good news is:
1) It is not a technically challenging job (if you can replace the front control arm bushings on your E46, then you have the necessary technical skills to do this DIY)
2) It can be done in one day, assuming that you've got all the necessary tools, parts and consumables. The job took me 10 hours non-stop, but if I knew then what I know now, I would've comfortably finished the job in about 6 hours.
A word of warning though; once you start this job, you need to be 100% committed to take it through to completion.
Bentley Service Manual
Garage jack and stands
Metric socket & spanner sets (+32mm socket for oil filter cap)
Torx socket set (both male and female)
Good quality torque wrenches (at least one for low torque ranges and one for medium - high torque ranges)
Torque angle gauge
Screw driver set
Fan removal tool (if you have auto transmission)
PPE: coveralls, gloves, safety glasses, headlamp
Bearing puller (if you decide to replace the control arm bushings while you're at it)
Engine support bar: I purchased one of these from eBay:
I've seen some DIY's utilising a hydraulic engine crane (cherry picker) for this purpose, but how is this any different to working under a car that's supported by hydraulic jacks? In my opinion, when installed correctly, a support bar is a much safer instrument.
(Note that I had to slightly modify the bar in the photo above, because the bar was designed to pivot under load and wasn't originally fit for purpose. Post below if anyone wants details of the simple modification)
Parts and Consumables
Engine oil (you'll need about a liter more than a usual oil change)
Oil filter (most come with a copper oil drain plug washer and oil filter housing cap o-ring)
A couple of cans of brake cleaner (or degreasing / cleaning agent of your choice)
Lots of shop rags
Non-hardening, oil resistant gasket sealer
1 x Oil pan gasket (P/N: 11-13-1-437-237)
1 x Oil dipstick guide tube O-ring (P/N: 11-43-1-740-045)
2 x Engine mounts (P/N: 22-11-6-779-970) - see note (iv) in the re-assembly section below
4 x Front sub-frame to frame rail bolts (P/N: 31-11-6-781-023)
4 x Control arm bushing carrier to body bolts (P/N: 33-30-6-760-652)
1 x Steering column universal joint clamping screw (P/N: 32-30-6-778-609)
Front end reinforcement to frame rail / suspension sub-frame bolts (number of bolts depends on whether your car is equipped with a reinforcement bar or plate) (P/N: 31-10-6-772-199)
Set of replacement front control arm bushings - see note (v) in the re-assembly section below
The steps outlined below more or less follow the flow of the procedure in the Bentley manual. Note that the instructions below are for a 2000 Coupe with manual transmission. You might have to make subtle adjustments to the job based on the configuration of your vehicle (just use common sense!)
The photos and diagrams in the Bentley manual are actually pretty helpful. The diagrams on RealOEM are helpful too. (Sorry, at the time of writing I didn't have any photo's to post with this DIY - it was a bit of a race against time - I'll be changing the engine mounts soon, so might take some photo's then)
1. Jack up the car and place on stands. Remove the front wheels.
2. Remove the splash guard and the chassis reinforcement plate (8 x bolts if you have a Coupe, like me)
3. Drain engine oil. Loosen and oil filter cap to allow oil to drain from the oil filter housing.
4. Remove the air filter housing (2 x bolts) along with the MAF sensor
5. Lift out engine fan assembly and remove both belts (marking the orientation of the belts)
6. Remove the (3 x ) power steering pump bracket bolts. All three bolts are different length - note which one goes where. Use stiff wire or rope to tie the P/S pump to the side, away from the oil pan.
7. Remove the oil dipstick guide tube:
a. Remove (1 x ) bolt from engine mounting bracket
b. Disconnect fuel line and wiring harness from the bracket
c. This should provide enough slack for the tube to be able to come out of the oil pan. You don't actually need to remove it completely.
8. Loosen the (2 x ) top engine mount nuts
9. Install the engine support bar and raise the engine approx 10mm (until the engine weight is supported).
10. Ensure that the steering wheel is centered. Take the key out of the ignition to prevent the steering wheel from being moved accidentally. Working under the car, carefully mark the position of the steering column shaft in the steering rack universal joint (see reassembly note (viii) on why this is important). Remove the (1 x ) torx screw and separate the shaft from the steering rack.
11. Disconnect the electrical harness connector at the oil level sensor
12. Remove the (2 x ) lower engine mount fastening nuts
13. Remove the left and right (4 x ) control arm bracket bolts from the frame rails
14. Detach the left and right front stabilizer bar anchors (4 x nuts) from the frame rails. Lower the control arm and move it to the front of the car, clear of the oil pan
15. Support the suspension sub-frame from below using a jack. Remove the (4 x ) sub-frame mounting bolts and lower the suspension. I lowered the sub-frame assembly (along with the steering rack) onto a pair of 5L oil bottles. Try to pull the sub-frame assembly as far forward as possible, so that it's clear of the oil pan.
Side note: This is where my procedure differs a little from the Bentley manual. In the manual, you're instructed to remove the control arm mounting nuts located on the sub-frame. This is no easy feat, while the sub-frame is still bolted to the car. I found that even if the control arms are left connected to the sub-frame, there is enough slack to lower the sub-frame assembly clear of the oil pan.
16. Remove the oil pan bolts. In total there are:
a. 21 x short 10mm bolts
b. 2 x medium 10mm bolts (heads hidden in recesses between the engine block and the transmission housing)
c. 2 x long 10mm bolts (heads exposed at the transmission end of the gasket)
d. 3 x torx bolts (connecting the transmission housing to the oil pan)
Make sure that you've removed all the bolts, before you start hammering on the oil pan to separate it from the engine block!
17. The oil pan should now be free to detach from the engine block. You will need to slide it forward about an inch to disengage from the transmission housing and it should drop out from there
18. Get cleaning! I spent a fair bit of time cleaning the inside and outside of the oil pan, as well as around where the pan comes in contact with the engine block. How do you know if you've installed the gasket correctly, if the oil pan is still covered with old engine oil? How will you know that there isn't something else leaking?
In general, reassembly is in the reverse order of disassembly. A few important notes (this is your chance to learn from my mistakes... I mean wisdom!):
(i) Make sure that you remove the old O-ring from the oil dipstick guide tube. Clean thoroughly around the guide tube and in the annulus where it mates with the oil pan (there was a lot of sand / dirt there). Coat the new O-ring with a bit of engine oil and install about half-way up the guide tube. Don't try to install the O-ring into the annulus on the oil pan, because you won't get the guide tube in.
(ii) The Bentley manual talks about applying "a small amount of non-hardening sealer... to oil pan gasket directly below joints... for end cover and timing case cover". This didn't make much sense to me before attempting the job and I've seen comments from a few forum members about the same thing. To clarify the statement in the Bentley manual: there are four seams on the bottom of the engine block, at the locations indicated in the picture (you'll see them once the oil pan and gasket are off). These seams intersect the oil pan gasket. Sealant is applied between the engine block and the top side of the gasket in those locations. I imagine that failing to do this step may result in oil leaking from those seams. Sealant was present on the factory oil pan gasket in those locations. The biggest difficulty I had with this step was that residual oil tended to collect and run along those seams on the low side of the gasket. So good luck with getting the mating surfaces clean and free of oil contamination! Also, getting the oil pan back on wasn't easy and I ended up smearing the sealer on the first attempt. This is where having an extra pair of hands could help.
(iii) Remember to tighten the oil pan bolts evenly. Install and tighten the (3 x ) torx transmission housing bolts last.
(iv) I strongly recommend replacing the engine mounts while you have the sub-frame off, if yours are original factory parts. I found that the leaking engine oil had started reacting with the rubber on the left mount and the rubber was all cracked on the right mount (proximity to exhaust?). The additional cost is nominal, compared to the size of the job to replace them later (which is what I ended up having to do). You will notice considerable decrease in noise from the engine, especially on gear changes. There is a 'key' on the underside of the bushing. Rotate the bushing to make sure the 'key' aligns with the recess on the sub-frame, as you're lifting the sub-frame back into place.
(v) If your car is still equipped with factory rubber front control arm bushings, this is a good time to replace them. Make sure you allow extra time for this task. The procedure is very well documented in these forums and YouTube.
(vi) I would strongly encourage you to replace the following bolts:
Front sub-frame to frame rail bolts
Control arm bushing carrier to body bolts
Front end reinforcement to frame rail / suspension sub-frame
Steering column uni-joint clamping screw
These bolts are either stretch-type or self-locking. Since you've gone to the effort of replacing the oil pan gasket the "kosher" way, may as well as follow the manufacturer's recommendations to replace these bolts.
(vii) Tightening torques (the important ones compiled for ease of reference - use common sense for the fasteners not listed below):
Oil pan bolts - 8.8 grade: 89 in-lb, 10.9 grade: 106 in-lb
Front sub-frame to frame rail bolts (10.9 grade) - 81 ft-lb
Control arm bushing carrier to body bolts (10.9 grade) - 42 ft-lb
Stabilizer bar to frame rail nut - 16 ft-lb
Steering column uni-joint clamping screw - 16 ft-lb
Front end reinforcement to frame rail / suspension sub-frame - Stage 1: 43 ft-lb, Stage 2: torque angle 90 degrees + 30 degrees
(viii) It is very important that you re-align the steering column shaft keyway exactly into its original position. Once the steering column shaft is disconnected, it doesn't take a lot of force to change the steering angle (on the steering rack side). Getting it wrong by even 1 notch will result in your steering wheel being tilted off centre by 10 to 15 degrees.
(xi) If you've replaced the front control arm bushings as part of the job, make sure you get a wheel alignment done. Hypothetically, a wheel alignment should not otherwise be necessary, upon completion of the oil pan gasket replacement. However, both times that I lowered the subframe, I found that the steering wheel didn't point straight afterward (despite taking every care not to upset the wheel alignment). Hence it's worth budgeting for a wheel alignment at completion of this DIY.
(x) Don't forget to replace the engine oil filter and refill with clean good quality oil.
Well, it's been a couple of months since I've replaced the oil pan gasket, I've travelled a couple of thousand km's and there is still no sign of any leaks from the new gasket.
Feel free to post questions / your experiences with this job and let me know if there are any errors in the procedure above.
Thanks for reading!
Impressive write up! Well done!
Nice write-up. The only thing I'd take exception to is the statement that "Polyurethane bushings are an excellent substitute." For some, either factory, Lemfoerder OEM, or Meyle rubber bushings would be a better choice. While there are benefits to poly bushings for the enthusiast, some find they transmit more noise than desired.
I am not looking forward to doing this...
As posted here and in the more thorough DIY above, this isn't difficult, but is tedious. If you don't have the Bentley manual, I would get one before starting this.
Thanks for the comments!
So I just completed the oil pan gasket DIY yesterday. Applied rtv sealant on all corners. I think it's still leaking, but quicker this time. I didn't use a torque wrench but I tightened all 21 bolts til it felt snug but didn't too much because I didn't want to strip anything. Any inputs??
Oil pan to block bolts are 10nm torque, with both Bentley and BMW instructions saying to tighten transmission bellhousing bolts last.
When I did mine, factory/Bentley recommended 3mm wide by 2mm high of RTV sealant. 2mm seemed a bit much, I think I did around 1mm high (and 3mm wide). Made sure the block surface was oil free before applying the sealant. Used Permatex Ultra Copper RTV sealant.
Used a BMW oil pan gasket.
No leaks after 15K miles.
Is it leaking all the way around the gasket, or just at the joints where you applied RTV sealant? Any photo's?
I found a small amount of oil around the gasket after I finished the job, but knew that it was the residual old oil that had leaked from the interior of the engine and onto the mating surfaces, as I was installing the new gasket (i.e. could tell by the color).
As I mentioned in the DIY, given that I didn't have the luxury of being able to leave the car up on stands for a few days to let all the old oil drip out and had to finish the job in a day; I literally found it impossible to get the mating surfaces clean. Hence why there was a bit of residual oil around, that had also made it into the RTV sealant on the low side of the gasket - not an ideal combination.
I used Permatex Ultra Black(R) RTV gasket maker from a brand new tube and bought a Bruss Oil Pan Gasket (although now that I think about it, the brand on the package was actually Meistersatz).
Insufficient torque on the oil pan bolts sounds like the most probable cause, if it is leaking all the way around (or the heaviest on the low side of the gasket). I used a torque wrench and tightened the oil pan bolts in a criss-cross pattern.
Hope that helps.
Thanks! ... and a question
This is a very helpful thread. I am in the process of renovating a 2001 325i sedan. It's been on jackstands for about a month now, getting new brakes and suspension, (Eibach / Bilstein / Meyle / etc. ... and I'm also going to take a crack at replacing the oil pan gasket, since there is oil dripping from several oil pan screw heads. I also have a new gasket for the filter housing, but that's not leaking, so I'm inclined to leave it alone, even though it's very accessible at this point. Anybody know of any FMEA work by BMW on these areas?
Question: How do you loosen the passenger side top engine mount nut? (I'm thinking long extension and u-joint type end on top of a shallow socket.
Since you have the car up on stands and already have a new OFH gasket, I would strongly suggest that you replace it while doing the oil pan gasket. In addition to the procedure for the sump gasket, it's just a matter of removing the alternator and the oil filter housing assembly. The OFH gasket is definitely a weak point on these cars and when it leaks in the future, it will undo all the time you would've spent on cleaning the oil off the engine while replacing the sump gasket.
As a final note, I went back to replace my engine mounts a couple of weeks ago and actually took photos of the disassembly this time. I'm planning on updating the DIY with photos in the near future, so stay tuned :D
Thanks for the quick reply !
Nice to know I didn't spend an hour and some bruised knuckles only to have overlooked a clever way to loosen that RHS engine mount! The top approach always seemed the most obvious. I just didn't have a long extension, or enough short extensions all one size to get a wrench handle in good position. I will pick up a long extension tomorrow after work and get that beyotch loose!
If I may ask, what mods did you do to your engine support bar? I just cranked my upright coupler tight and pinched it into position. Looks like the J bolt under load should prevent it from rotating too far either way since the load is just below the bottoms of the support feet.
Engine Support Bar Mods
As requested, here are a few photos of the mods that I had to make to the engine spport bar.
The biggest issue that I had was that the bar was able to rotate about the east-west axis, when installed onto the car. To stop the rotation, I drilled holes into the plates:
This pic shows how much slack there was with the bolt through the original holes (hence there's no way I could pinch the upright coupler into position):
This pic shows how much the bar was originally able to rotate about the east-west axis (relative to being installed on the car):
A close-up, showing how much freedom of rotation there was originally:
What the engine support bar looked like with the modifications applied:
A close-up of the upright coupler, with the modification applied:
Hope this helps.
I made good progress today. Replaced the voltage regulator in my Bosch alternator, replaced the oil filter housing gasket, replaced the oil pan gasket, reinstalled the PS pump and alternator and belts. Unfortunately, my replacement subframe bolts didn't arrive, so I reattached the subframe with the old bolts, and I'll leave it on the jackstands until the new bolts come in, and just replace them and torque one at a time.
I also reused the guibo bolt, but that one is also relatively easy to get to, and since I had the entire front suspension disassembled, I'm not really sure whether my steering wheel is going to line up right - so I'll probably install the front lower control arms next, and see how the wheels are going to line up. Because the front spindles were swinging free on the struts, I don't think there was a lot of push on the steering rack during manipulations, but I didn't always have the ability to look.
I'd say that the job was not too hard, and would have been entirely pleasant except for that &*%%$% top driver's side torx bolt that goes forward into the pan from the tranny housing. I had to use my smallest 1/4 inch drive wrench to be able to get on it, and only had one ratchet click worth of swing. TEDIOUS!!! No way to torque it, so I just used feel. It's not a gasketed joint, so if the torque is not entirely uniform for those three bolts, it won't be too big of a deal.
I also replaced my motor mounts during this process, and forgot to add the heat shield on the passenger side. Since I was reusing the crossmember bolts anyway for the time being, I just loosened the drivers side of the crossmember enough to let it drop but not far enough to disconnect the guibo, and then supported the crossmember on the jack, and removed the bolts from the passenger side. I was able to lower that side enough to get the mount out, fit the heat shield and get it back in pretty easily.
The other little problem I had was that the rubber cushion on the crossmember, somehow became dislodged, and it was very difficult to get it reinserted completely. Still not sure it's little rubber tooth was all the way seated in the crossmember hole, but it's in proper position, and I couldn't poke it out with moderate finger pressure, so good enough I suppose.. I'll get one more crack at checking it if it turns out that I need to adjust my steering wheel position. Otherwise, it will stay as is.
Once again I want to thank anonymous-coward for posting this thread. It was a very thorough and well organized procedure that was easy to follow.
That's fair enough, however there are engine support bars on the online market that look the part in the photos, but aren't quite fit for the purpose of this DIY (like mine). So I figured it would be worth the mention in this thread, for those who may want to attempt this procedure and are looking at buying an engine support bar.
I'm happy to hear that this DIY was helpful! Let us know how it goes once you've got the car back on the road.
Hey, this is a *great* DIY! It follows the Bentley procedure very well, which is reassuring.
I did this several weeks ago on my '99 E46 328i (Left Drive) and it worked great. Of course it was still a struggle. I had my son for help for most of it, which made it easier at certain steps. I only have a few comments:
1. When separating the steering coupler, do it at the top connection and you won't have any alignment issues. It is keyed and will only go in at 180 degree intervals, so you really have to try to get it wrong. BTW, this step is a royal pain in the A$$.
2. I did not replace the subframe or steering coupler bolts. I will replace the subframe bolts soon, as I intend to track the car. Otherwise, I'm not sure replacement would be necessary.
3. I was not sure about some of the torque specs to use. I could not tell what grade some of the bolts were, so I just used the mid or high spec.
4. I was able to get a torque wrench on all but two of the oil pan bolts. I checked them a second time, which is good because I missed a couple.
5. You do not need to separate the inner ball joints, but you must unbolt the front CAB's. For most of the time I supported the driver side of the subframe with a jackstand. During the pan removal and install steps, I let the subframe hang temporarily by the power steering hoses. That gave me enough clearance to get the pan out/in. Most of the weight is supported by the struts, so I think that's ok.
6. When removing the pan, you must clear the oil pump sprocket in front, and the pickup in the rear. Slide the pan forward to clear the trans bellhousing, then down to clear the pump, then backward and out.
So far, no evidence of leaks. I need to get it back up on jackstands and remove the plastic shield to inspect it again to make sure. Will update to let you know.
Update: After a couple of weeks of 50 mi/trip commutes I put the car on jack stands and looked it over. No leaks from the oil pan that I could see, but three wet spots on the bottom of the pan. The front one looks like PS fluid and I think the return line is leaking. The middle one I can't tell where it's from, and the rear looks like it might be the main seal. Wouldn't be surprised at 230K; will do it when I get around to the clutch (still original). Anyway, the oil pan gasket itself looks good!
Double post. Sorry.
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