Access to the following:
- Oil Separator Valve (also known as: Pressure Regulating Valve, Crankcase Ventilation Valve CCV, PVC valve)
- Idle Control Valve (ICV)
- Intake Manifold Resonance Valve (also known as: DISA Valve)
This is a journal of the work I did on my car: a 2001 BMW 325i E46 sedan, auto transmission. To the best of my recollection, the following tools, parts, and procedures were used.
The instructions given as well as tools used are for reference only. Adjust the size (increase/decrease) of the sockets and torx fasteners that best fit your vehicle. You are responsible to cross check all part numbers listed are suitable to your car
Due to the extensive parts, connectors, and procedures, the level of difficulty of this project is high. Some have rated it as a 7 or 8 based on a 1-10 scale: oil change being level 1 and engine rebuild as level 10. Allocate at least 5 - 7 hours of work depending on your level of mechanical proficiency.
- T-40 & T-25 Torx fasteners
- 1/4" and 3/8" drive
6mm, 10mm, & 13mm sockets
Extension bars, various lengths
- Throttle body cleaner
- Small Mirror
- Screw driver
- Magnetic pick up tool
- 6 mm reversible ratchet wrench - For less than $10.00, this will pay for itself especially for hard to access lower air intake boot clamps
- Assembly lube
- Electrical connector cleaner
- Dielectric lubricant
- Hose cutter, i.e. small blade knife, pipe cutter or similar.
11617501566 Oil Separator
11611432559 Oil Separator Hose to Valve Cover
11157532629 Oil Separator Oil Dip Stick hose
11617504535 Oil Separator Connecting Hose
11617504536 Return Pipe from Connecting Hose
13541435627 Air Intake Boot; Lower
11431740045 O-Ring Oil Dip Stick Tube to Oil Pan
11611716174 Throttle Housing Gasket
If your car is subject to extreme cold climates, get the "cold climate" version of the Oil Separator Valve (11617533400) and Oil Separator Hose to Valve Cover hose (11617533398). Both parts will cost more.
Optional (get if budget allows)
11611437453 ICV rubber grommet
- Although the 4 plastic hoses associated with the oil separator are unreasonably expensive, it is recommended to replace them. These plastic hoses get hard and brittle due to age and the heat/cold cycles they are subjected to. The older the car, the greater the likelihood the connector/hose will break during removal. These connectors are easy to connect but can be a challenge to disconnect especially in the confined area they are in. To facilitate removal, sometimes it is better to cut the old hose rather than deal with the connector. Prior to installation, practice connecting/disconnecting the parts to each other.
- Raise the front of the car either by using jack stands or ramps. This working position makes it easier to access the work area. In addition, you may need to access the car from underneath, although I did not have to this.
- To detach the various electrical wiring harness connectors, push down the metal wire clip and pull the connector out to disconnect. To re-install, simply reinsert connector until you hear the metal clip click. Pull and tug the connector to check if it is secure.
- Although the electrical wiring harness connectors are individually keyed to prevent cross connection, it is good practice to place a label on the connector and the unit that it attaches to. This way you do not accidentally force a connector where it does not belong. In addition, count the number of wiring connectors you are disconnecting. It is easy to miss a connector during installation.
- Label the screws, clamps, and bolts or tape it to the removed part so during installation the part will be where it belongs.
- Take several digital pictures as you go along during removal to serve as reference just in case you forget how things go.
- Although not necessary, it is a good idea to clean the electrical connectors with electrical spray cleaner and lightly coat it with dielectric lubricant.
- Lightly lubricate the ports of the new hoses with assembly lube to ease assembly.
- Check the condition of surrounding vacuum lines and hoses. If replacement is necessary, the vacuum lines and hoses maybe acquired through your local auto parts supplier.
Now the fun begins. It is best to remove the following parts in the order given.
1. Turn off the car and disconnect the battery.
2. Micro-filter housing assembly. Photo 1
- Remove micro filter plastic cover - 3 half-turn clips
- Remove micro filter
- Cable harness cover - lift clips to release cable harness
- Remove 4 T-40 torx screws located underneath the micro-filter
- Remove micro-filter housing
3 . Fuel rail cover. Photo 1
- Use small screwdriver to lift and remove 2 plastic caps
- Remove 2 10mm bolts holding fuel rail cover
4. Front air duct. Photo 1
- Remove 3 plastic expanding fasteners. Raise middle pin and pull out expanding fastener.
5. Mass Air Flow sensor (MAF) Photo 1
- Disconnect wiring harness to MAF sensor
- Loosen hose clamp between MAF and upper air intake boot
- Leave MAF connected to the air filter box
6. Air filter box assembly. Photo 1
- Detach wiring harness behind air filter box
- Remove 2 10mm bolts on air box base
- Notice location of a rectangular plastic air channel coming from the front (near radiator) of air filter box. This may come off during removal. Reattach air channel during installation
- Remove both air filter box and MAF as a unit. It is not necessary to separate from each other
7. Air intake boot -upper. Photo 1
- Disconnect vent "F" shape plastic vent tubing coming from top of the upper air intake boot. The "F" shape tubing breaks easily and maybe difficult to remove so another option is to leave the vent tubing attached and fiddle with air intake boot so it can sit on top of the intake manifold
8. Middle air intake boot connector
- Loosen both hose clamps
- Remove the hard plastic connector
9. Oil dipstick guide tube. Photo 2
- Detach wiring and vacuum lines hanging from oil dipstick guide tube
- Remove oil dip stick
- Detach or cut off the Oil Separator Dipstick Hose from the guide tube
- Remove 13mm bolt holding oil dipstick bracket to the engine
- Remove any dirt surrounding base area of the dipstick housing to prevent any dirt from falling into the engine. Raise the guide tube straight up. The base rod extends about 2 -3 inches into the engine. Oil will not spill out when the oil dipstick housing is removed as long as crankcase is not overfilled.
- Replace o-ring at base of the guide tube
- Insert a plug onto the engine opening to prevent anything from falling in
- Important: Clean the inside of the guide tube going to the oil separator. Any blockage will likely cause premature failure to the new oil separator.
10. Heat shield. Photo 1
- Remove 2 quarter-turn twist fasteners
- Move hose and rubber strip out of the way
- Remove heat shield
11. Lower air intake boot. Photo 3
- Before removing this boot, use a small mirror to view the large rubber tab at its base. This tab aligns between 2 raised guidelines located on the outside bottom of the throttle body port. Align the tab during installation
- Loosen 2 hose clamps - throttle body port and Idle Control Valve port
- Remove lower air intake boot
- Unlike the upper air intake boot, the lower air intake boot will likely need replacement. The small elbow tube of the lower air intake boot is susceptible to splitting. Considering how inexpensive it is, it is best to replace the part.
12. Intake Manifold Resonance Valve, also known as DISA Valve. Photo 4
- Disconnect wire harness to the DISA.
- Remove 2 T-40 Torx screws
- Carefully and gently remove the DISA valve.
- Use throttle body cleaner to clean butterfly flap
- Clean and inspect condition of the gasket. To repair if required, use sensor-safe RTV gasket
13. Wire harness box, Photo 4, 5, and 6
- Remove 3 10mm nuts holding bracket. One of the nuts is well hidden at bottom right of the throttle body, next to one of the throttle body bolts. You will need a mirror to view its location, see Photo 5
- To move the wire harness box aside disconnect additional wire harness connectors, i.e. alternator, oil pressure and temp switch
14. Fuel Tank Venting/Breather Valve. Photo 6
- Disconnect wire harness to the Fuel Tank Venting Valve
- Slide out Fuel Tank Venting Valve from its mounting bracket. There is no need to remove connecting hose
15. Fuel Tank Venting/Breather Valve mount bracket. Photo 6
- Remove 2 T-25 mount bracket screws
16. Idle Control Valve ICV. Photo 5 & 6
- Disconnect wire harness to the ICV
- Remove 2 T-40 bracket screws and remove bracket
- The port end of the ICV toward the manifold is held via friction to a rubber grommet - pull out ICV to remove. You may need to use a bit of force to pull ICV out. Clean rubber grommet and lightly coat with clean engine oil to ease reassembly. If the rubber grommet is hard and no longer pliable, replace it.
- Use throttle body cleaner to clean the ports and valve
17. Throttle Body. Photo 5
- Disconnect wire harness to the Throttle Body
- Remove 4 10mm bolts - outside corners
- Clean ports and butterfly plate with throttle body cleaner. Do not play with the butterfly plate. Replace the throttle housing gasket
18. Return Hose - Photo 6 & 7
- The Return Hose connector that is close to the firewall is difficult to disconnect due to the limited space. Insert a screwdriver between the fuel rail and locking ring to pinch the plastic locking ring, and coming from the opposite position, press the other side of the locking ring with your finger and pull out hose. Another easier option is to cut or snip off the plastic locking connector rings with a blade or wire cutter. Without the locking ring, pull connector out.
- Disconnect the other end of the connector attached to the Connecting Hose.
19. Oil Separator Hose to Valve Cover. Photo 7
- Notice: The 90 deg elbow of this hose goes to the valve cover and the other end goes to the oil separator. Keep this in mind during installation.
- Squeeze hose locking rings and pull to disconnect. If the connector attached to the Oil Separator is difficult to remove, cut the hose to ease removal.
20. Oil Separator Connecting Hose. Photo 7 & 8
- Unlike the other 3 hose connectors, the connector going to the oil separator does not use a locking ring. Slight curl the flex hose to get clearance and twist hose counter-clockwise to turn the connector until it stops. Then pull out hose to disconnect. Practice with your new parts to understand the mechanics of the connector.
21. Oil separator. Photo 8 & 9
- Remove 2 T-25 screws holding Oil Separator.
- Important: Note that the Oil Separator has a small port covered with a rubber plug. Some models use this port and some models do not. For the models that use this port, the vacuum hose will likely need replacement. Check your local auto parts store for a suitable hose replacement.
1. It is best to do the installation in the reverse order given above. Do line 21, 20, 19 and so on.
2. During assembly of the Oil Separator valve, first fasten the Oil Separator to the engine. Then insert the flex connecting hose through the manifold intake passage way. Curl the flex hose to get clearance, and insert connector onto the Oil Separator port turning the hose clockwise until it stops. Important: Tug on the hose to make sure you have it on securely.
3. Make sure all hose connectors and electrical connectors are secure. You will hear a "click" as you fasten join the items. To test, tug and pull the connector to make sure it is secure.
4. Stop and take a break. Go slow especially during installation and review carefully all electrical connectors and all hoses making sure they were installed correctly. You do not want to redo the job just because you left out a connector.
I hope the instructions and pictures shown bring the complexity of the project down a level or two.
Work on the project at your own risk. Information given is for reference only.