The M20 oil pan does one quiet job until the day it does not. It stores the oil, it seals the bottom of the engine, and it carries the oil pump inside it. The gasket goes hard and weeps onto your driveway, or somebody finds a rock and tears a hole in the stamped steel, and now you are pulling the pan. The good news is the factory way is simpler than the internet makes it look. You do not have to hoist the engine on a six-cylinder car. You drop the steering rack a couple of inches, pull a cover plate, and the pan comes down with the pump still bolted to it.
This covers the one-piece pan on the M20 cars: 325e, 325es, 325i, and 325is. If you have a four-cylinder 318, you have a two-piece pan and a slightly different job.
Read This First: Safety
Work on a cold engine and get the car up safely. Drained oil is hot if the engine just ran, so let it sit and watch your hands when the drain plug comes loose. This whole job happens on your back under the car, so it has to be solid: jack stands rated for the weight, on the factory front jacking points, on level concrete. A floor jack alone is not enough to crawl under. Chock the rear wheels.
One more, and it is the one the forums skip. You are about to unbolt the steering rack from the subframe and let it hang a couple of inches. That is fine and the factory does it, but do not turn the steering wheel with the rack loose, and support the rack so it is not hanging by the hydraulic lines. Snug those two bolts back to spec when you are done, because they hold your steering to the car.
Before You Start
This is the six-cylinder pan. The M20 in the 325e/es/i/is runs a one-piece steel pan with the oil pump bolted up inside it. The four-cylinder 318i and 318is use a two-piece pan (an upper and a lower section) that comes apart differently, so if you are counting four spark plug wires, this is not quite your procedure. Six wires means you are in the right place.
You do not need an engine hoist. This is the big one. A lot of the old write-ups have you lifting the engine off its mounts with a cherry picker, unbolting control arms, the works. The factory procedure is far less dramatic: drop the steering rack two bolts, pull the bellhousing reinforcement plate, and the pan clears. If somebody is telling you to hoist the motor to change a six-cylinder pan, they are doing it the hard way.
Have a new gasket and a new drain plug washer on the bench before you start. You are in here for the gasket, so it gets replaced no matter what the old one looks like. The aluminum (or copper) crush washer under the drain plug is a one-time part too. Reusing it is how a fresh pan job still drips.
If the pan itself is torn or rotted, replace the pan, not just the gasket. A rock strike or rust-through means a new pan. While the old one is off, look at the oil pump pickup and the filter screen inside the pump, because you will never have a better chance to clean them.
What You're Replacing
You are renewing the gasket that seals the pan to the block, and the pan itself if it is damaged. The pan is one piece on these cars and the oil pump lives inside it, bolted to the block where you cannot see it until the pan is down.
| Part | OEM part no. | Notes |
|---|---|---|
| Oil pan gasket | 11 13 1 730 234 | The reason you are here. One-piece gasket between pan and block on the six-cylinder. Always renewed. |
| Oil pan (sump) | 11 13 1 720 754 | Stamped steel. Replace only if torn, dented into the pickup, or rusted through. |
| Drain plug sealing washer | 07 11 9 963 151 | The crush washer under the 17 mm drain plug. One-time use, replace it every time. |
| Oil level sensor O-ring | n/a | The sensor threads into the top of the pan on six-cylinder cars. Inspect its O-ring and replace if crushed. |
| Oil pump pickup screen | n/a | Not a wear part, but clean it while the pump is in your hand. |
| Ground strap | n/a | A braided strap bolts to the pan. It has to go back on, see the steps. |
The gasket is cheap and engine-specific, so confirm the part against your VIN before ordering. If you are also replacing the pan, the six-cylinder pan is its own part, different from the four-cylinder, so order by chassis and engine.
What You'll Need
| Part | OEM part no. | Notes |
|---|---|---|
| Oil pan gasket (M20, one-piece) | 11 13 1 730 234 | The six-cylinder gasket. The four-cylinder 318i uses a different one (11 13 1 727 974). |
| Drain plug sealing washer | 07 11 9 963 151 | New A12x17 aluminum crush washer, every time. |
| Oil pan (optional) | 11 13 1 720 754 | Only if the old one is torn or rusted. Six-cylinder specific. |
| Oil level sensor O-ring | n/a | If yours is crushed or weeping. Comes with the sensor; no separate common part number. |
| Engine oil and filter | n/a | You drained it, so refill with fresh. Roughly 5 quarts plus a filter. |
| Gasket sealing compound | n/a | A non-hardening sealer (Permatex or Wurth type) for the timing-cover and end-cover joints only. |
These are the genuine BMW numbers for the M20 six-cylinder E30. The four-cylinder 318 pan and gasket are different parts, and BMW has superseded some numbers over the years, so confirm each against RealOEM or FCP Euro by your VIN before ordering.
| Tool | For |
|---|---|
| Jack and two rated jack stands | Getting the car up and holding it. Non-negotiable |
| 17 mm wrench or socket | The drain plug |
| 10 mm socket, swivel, and extensions | The pan bolts. There are a lot of them and some hide |
| Torx sockets (E-Torx / external) | The bellhousing reinforcement plate has Torx-head bolts |
| Drain pan, 6 qt or larger | Catching the oil |
| Gasket scraper or plastic razor | Cleaning the old gasket off the block. Do not gouge the alloy |
| Torque wrench (low range, Nm) | The pan bolts are low torque and it matters |
| Rubber or dead-blow mallet | Breaking the pan loose. Never pry it |
Step 1: Drain the Oil and Disconnect the Level Sensor
With the engine cold, put the drain pan under the 17 mm drain plug and pull the plug. Let it drain fully. The factory note here is a good one: pull the loose plug away from the hole quickly so the oil does not run down your arm. Keep the old sealing washer with the plug so you remember to swap it.
While that drains, disconnect the oil level sensor harness connector. On these six-cylinder cars it is down at the base of the alternator, not at the pan itself. Unplugging it here saves you fighting the wire later. It is also a good time to disconnect the battery.
NOTE: The oil level sensor is a six-cylinder-only part, and it threads into the top of the pan on the driver's side. Do not yank the pan down with the sensor still wired up.
Step 2: Get the Car Up and Support It
Raise the front of the car on the factory jacking points and set it on two rated jack stands, as high as you can safely go. The more room under there, the easier this is. Chock the rears, and give the car a shove to confirm it is not going anywhere before you slide under.
Step 3: Drop the Steering Rack a Couple of Inches
This is the move that makes the whole job sane, and it is the one the engine-hoist crowd never mentions. The steering rack crosses right under the front of the pan. Remove the two bolts that secure the steering rack to the subframe and let the rack drop down a couple of inches. You do not disconnect any hydraulic lines, you do not pull the rack off the car. You just free it from the subframe so it can sit low and out of the pan's path.
Support the rack so it is not hanging on its lines, and leave the steering wheel alone from here on.
CAUTION: Those two rack bolts hold your steering to the subframe. They go back to 42 Nm (31 ft-lb) on reassembly. Note where they came from and do not lose them.
Step 4: Remove the Bellhousing Reinforcement Plate
There is a stamped plate at the back of the pan that ties the engine to the transmission bellhousing and overlaps the rear of the oil pan. It hides the last few pan bolts, so it has to come off. It is held by four hex-head bolts and four Torx-head bolts. Get all eight out and pull the plate down.
The forum threads argue about whether you need Torx for this, and some cars apparently came with mixed heads over the years. Have both an external Torx set and standard metric sockets handy so you are not stuck halfway. The bolts can be different lengths, so lay them out in order as they come off.
Step 5: Unbolt the Ground Strap and Drop the Pan
A braided ground strap bolts to the pan. Take it off and set the bolt with it. This matters more than it looks: a missing or forgotten ground strap can leave you with a no-start when you are done, so make a mental note to put it back.
Now remove the oil pan retaining bolts. There are a lot of them around the flange, they are 10 mm heads, and a couple sit in tight spots where you will want the swivel and a long extension. A cordless impact or driver speeds up the easy ones. Get every last one out, then lower the pan.
If the pan does not drop free, tap it loose with a rubber mallet. Do not pry between the pan and the block with a screwdriver. The block flange is aluminum and one scratch there becomes a leak you cannot fix without pulling the pan again.
CAUTION: Never pry the pan off with a sharp tool. A gouge in the block or pan sealing surface means a leak no gasket will cure. Tap, do not pry.
Step 6: Free the Oil Pump and Withdraw the Pan
On the six-cylinder, the oil pump bolts to the bottom of the block and sits inside the pan. To get the pan all the way out, remove the three oil pump mounting bolts, lower the pump and its drive shaft down into the pan, and then withdraw the pan and pump together as one piece. The pump comes out with the pan, not separately.
With the pump in your hand, this is the moment to unscrew the cover from the oil pickup and clean the filter screen. Years of sludge collect there. When you reinstall the cover, line up the notch in the cover with the notch in the pump body, that orientation matters.
NOTE: This is the one thing worth doing even if you only came for the gasket. You will never have an easier shot at the pump screen, and a clogged pickup is its own way to kill an engine.
Step 7: Clean Both Sealing Surfaces
Set the pan on the bench and scrape every trace of old gasket off both the pan flange and the block flange. The forum is honest about this part: there will be a lot of it, and it is tedious. Take your time and use a plastic razor or a proper gasket scraper, not a steel blade dragged hard across the alloy. Wipe both surfaces down with brake cleaner until they are bare and dry. A clean, flat surface is most of what makes a gasket seal.
While you are here, look at the front timing-cover joint and the rear end-cover joint where they meet the pan gasket. Those two corners get a thin smear of sealing compound on reassembly, the long flange faces do not.
Step 8: Reinstall the Pump, Then the Pan with a New Gasket
Bolt the oil pump back to the block first and torque the three mounting bolts to 22 Nm (16 ft-lb). Make sure the suction line seats cleanly.
Lay the new gasket on. The pan gasket is not symmetrical, so check the orientation against the bolt holes before you commit. A few small dabs of sealer can hold the gasket to the pan while you line it up, but keep it light.
CAUTION: Go easy on the sealer. Too much can squeeze into the pan and plug small oil passages once it circulates, and that leads to oil starvation and a wrecked engine. A thin film at the two cover joints is all the factory asks for, never a thick bead all the way around.
Offer the pan up, start every bolt by hand, then snug them. Torque the oil pan bolts to 9 to 11 Nm (7 to 8 ft-lb). That is hand-snug, not gorilla-tight. Run them down in a crossing pattern so the pan pulls down flat and even. The forum says "just snug, don't go super tight," and for once that lines up with the book: 9 to 11 Nm is genuinely light, and overtightening warps the flange and starts the next leak.
Step 9: Reassemble, Refill, and Check for Leaks
Work back out in reverse:
- Bolt the ground strap back to the pan. Do not skip this, it is the no-start the old hands warn about.
- Refit the bellhousing reinforcement plate with its hex and Torx bolts in their original spots.
- Raise the steering rack back to the subframe and torque the two rack bolts to 42 Nm (31 ft-lb).
- Fit a new drain plug sealing washer and reinstall the drain plug.
- Reconnect the oil level sensor connector at the alternator, and reconnect the battery.
Now refill. The M20 takes roughly 5 quarts of fresh oil with a new filter. Add through the cap on the valve cover, then check the dipstick on level ground and bring it to the MAX mark, no higher. Too much oil is as bad as too little.
Start it and let it idle. Watch the oil pressure light go out promptly, then get under there with a light and look hard at the pan flange, the drain plug, and the pump area for the first sign of a weep. Shut it down, recheck the level, and look again the next morning for drips on the floor. A clean cardboard under the car overnight is the honest test.
Troubleshooting
It still leaks after the job. Almost always the surfaces were not clean or a bolt is uneven. Pull it back down, scrape both flanges truly bare, confirm the gasket orientation, and retorque in a crossing pattern to 9 to 11 Nm. A second look usually finds old gasket you missed in a corner or a drain plug that needed its new washer.
The car cranks but will not start after reassembly. Check the ground strap on the pan first. A forgotten or loose pan ground strap is the classic E30 no-start after this job, and it is a two-minute fix.
The oil pressure light stays on at idle. Stop the engine. Do not drive it. Either the pickup was not seated, the pump bolts backed off, or the pump cover notch is misaligned. The light staying lit means low or no pressure, and running it that way is how you turn a gasket job into a rebuild.
The pan will not come down past the steering rack. The rack has to actually drop, not just unbolt. Make sure both rack-to-subframe bolts are out and the rack has sagged clear. If it is still tight, you have more room with the car higher on the stands.
You scratched the block flange with a scraper. A light scratch can sometimes be sealed with a thin film of compound, but a real gouge means the surface will weep. Clean it, assess it honestly, and if it is deep you may be chasing that leak until the surface is dressed flat. This is exactly why the rule is tap, never pry.
A Note on Doing It the Easy Way
If you have read the old forum threads, you have seen people hoist the engine, drop the subframe, and unbolt control arms to change this pan. You do not need any of that on a six-cylinder car. Two rack bolts and a cover plate is the whole trick, and it is the factory method. Save the cherry picker for the day you actually pull the motor.
Wrap-Up
You dropped the pan the factory way, cleaned the pump pickup while it was in your hand, sealed the new gasket on bare flanges, and set the pan bolts to a real torque instead of guessing. Fresh oil, a new drain washer, the ground strap back on, and the rack bolts to spec. Keep a cardboard under it for a couple of nights to confirm the weep is gone, and this engine stays where its oil belongs. For the rest of the chassis, see our BMW E30 Torque Specifications guide.
Got questions? Tag us on socials or hit us at info@treedylabs.com. Show us the build when it's done. We actually want to see it.