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Old 10-06-2012, 10:33 PM   #1
Registered User
Join Date: Oct 2012
Location: Melbourne, VIC
Posts: 15
My Ride: 2000 320Ci
DIY - Oil pan (sump) gasket replacement

Hey guys,

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.

Standard Tools
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
Rubber mallet
Fan removal tool (if you have auto transmission)
PPE: coveralls, gloves, safety glasses, headlamp

Specialised Tools
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?

Reassembly notes
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!

Last edited by anonymous_coward; 01-06-2013 at 12:29 AM. Reason: Rev-2: Uploaded photos and other minor amendments
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