BMW E46 Common Leaks

This guide is a work in progress and will be continually updated.

Any owner of the BMW E46 will encounter fluid leaks. The following guide will shed some light upon common leaks.

1. Valve Cover Gasket (VCG) leak
This happens to every E46 eventually. They mostly leak on the passenger side of the motor near the rear of the valve cover on top of the heat shield for the bank 2 exhaust manifold. It will look like so:

Part numbers needed for the fix:
Valve cover gasket set: build date before 9/02 11-12-9-070-990
build date after 9/02 11-12-0-030-496
Grommets: 11-12-1-437-395 (Qty 15)

2. Oil Filter Housing Gasket (OFHG)
This one is tough to see from the top of the engine. Most of the time you will just notice oil in the splash shield and eventually on the ground. Driver side of the motor, under the oil filter housing where it bolts to the block. I’ll let the pictures do the talking. Second picture is what the leak looks like with the housing removed.

Part numbers needed for fix:
Oil filter housing gasket: 11-42-1-719-855
Crush washers: 32-41-1-093-596 (Qty 2)

3. VANOS oil line
These hoses usually won’t have a dripping type oil leak but will leak very slowly and start to build up residue. It bolts to the oil filter housing and to the VANOS unit.

Part numbers needed for fix:
VANOS line: 11-36-1-705-532
Crush washers: 32-41-1-093-596 (qty 4)

4. Oil separator drain tube
If you have never done your oil separator and hoses, you need to at least check this hose. Most of the time this hose is severed in half and is all covered in residue. The residue can run down the dipstick tube and make it look like the dipstick tube o-ring is leaking. This one was tough to find a picture of one.

It is on the right in this picture connected to the dipstick tube.

Lower hose in this picture

Part number needed for fix:
Drain hose: 11-15-7-532-649
Drain hose for cold weather package with insulation: 11-15-7-532-629

5. Power steering hoses at the reservoir with cap o-ring
While not technically an “oil” leak I will still cover these as they leak horribly. Some people stop the leaks by just replacing the clamps if the hoses are in okay condition while some people replace the hoses. Which you do is up to you. If your reservoir is also covered in residue, replace the cap o-ring.

This is what the reservoir looks like with a leaking cap o-ring:

Part numbers needed:
If just doing clamps: 07-12-9-952-109 (qty 2)
If doing hoses:
If built before 9/01 32-41-1-095-526 and 32-41-6-796-390 along with clamps above.
If built after 9/01 32-41-6-750-155 and 32-41-6-796-390 along with clamps above.
Cap o-ring: 32-41-1-128-333

6. Oil pan
Usually only common on higher mileage cars but can happen to any of them. Now alot of times other oil leaks can leak down and around the oil pan and make you think your oil pan is leaking which is why I highly recommend cleaning up the oil and thoroughly inspecting the leak before just replacing parts.

Part number needed: 11-13-1-437-237

7. Rear main seal
Usually on higher mileage cars as well. It leaks between where the transmission mounts to the engine. This is not an E46, but is what it looks like when a rear main seal leaks.

Here is a picture of the actual rear main seal that is leaking on an E46 with trans removed:

Part number needed:
Rear main seal kit: 11-14-1-438-274
Just the seal: 11-14-2-249-533
I recommend doing the kit as it comes with the mounting plate and the gasket for the plate. Its always better to replace it while you are in there. Plus if you do just the seal you have to make sure you have it seated flush when you install it. If you buy the kit, it comes seated in the housing already.

8. Automatic transmission pan gasket
This leak will look similar to the oil pan leak except for with transmission fluid. If you have a leak on the ground near the center of the car with a reddish fluid this is probably it. The fluid can also have a brown color if it has alot of age to it. So it can easily be mistaken for oil. An easy way to tell the difference is the smell. Oil and the trans fluid have a completely different smell.

(I’m having a hard time finding a good picture of an E46 with a trans pan leak, if anyone has a personal one, let me know so I can add it.)

Part number needed for fix:
These part numbers vary greatly as there are different transmissions that have been installed in e46’s. There is also multiple different fluids. To be sure of your part number for your pan gasket you can PM me or ask in this thread, just give me the last 7 digits of your VIN and I can provide you with the number. For the fluid part number, there should be a label on the pan of your transmission with the fluid part number. I can also look that up for you if needed.

9. Differential output seals

Part number needed for fix:
Diff output seals: 33-10-7-505-604 (qty 2 needed if doing both sides.)

10. Oil pan drain plug
This leak can happen because the drain plug gasket isn’t replaced when the plug is removed, because the gasket isn’t there, or if the plug isn’t properly tightened. It can run down the oil pan and sometimes make it look like the pan is leaking. I couldn’t find a pic of one actually leaking but the plug would be covered in oil and residue all around it. Here is a picture of the drain plug.

Part number needed for fix:
Drain plug gasket: 07-11-9-963-151
Drain plug: 11-13-1-273-093 (if needed)

11. Power steering pressure hose
This is one of the other power steering hoses that can leak. These leak from the crimp seams and build up alot of reside on the rubber portion of the hose.

Part number needed for fix:
For the part number on this, it depends on which pump you have installed in your car. Ever since BMW changed the style of the pump, the pressure hose changed as well. They changed where the pressure hose mounts to the pump therefore the new style hose has different bends. The new style hose part number is 32-41-6-764-725. The old style hose part number is 32-41-6-774-215. The new style hose has only one bend in the metal pipe near the pump that is about a 110 degree bend or so. The old style has 2 bends near the pump.

12. Differential rear cover gasket
This isn’t all too common on these cars but it can eventually happen with age and higher mileage. On this picture…it looks like both the axle seals and the diff cover gasket are leaking. It leaks all over the cover and around the bolts. It will build up residue like in the picture.

Part needed for repair:
BMW no longer offers a gasket for this, they stopped making it and have instructed everyone to use RTV silicone to reseal the cover.