The following information is provided for reference purposes only and should be used at your own risk. Moreover, in no event shall Beisan Systems, LLC or its members be liable for any incidental, consequential, or special loss or damages of any kind, regardless of the cause. 6-cylinder Double Vanos Procedure includes any issues related to the 6-cylinder Double Vanos system.
Introduction
“Vanos” is BMW’s name for its variable valve timing units. Vanos units take on various shapes and design according to car year and model (engine model). The Vanos discussed here is BMW part # 11-36-1-440-142. It’s a double Vanos; meaning both the intake and exhaust valve timing is varied.
The 6-cylinder Double Vanos Procedure involves the Vanos unit, which is a key component of BMW 6-cylinder engines such as the M52TU, M54, and M56. To provide context, car manufacturers incorporated these engines into a wide range of models produced between 1998 and 2006. Specifically, you can find these engines in the 3-series E46 (98-05), 5-series E39 (99-03) / E60 & E61 (02-05), 7-series E38 (98-01) / E65 & E66 (02-05), Z3 E36 (98-02), Z4 E85 (02-05), X3 E83 (03-06), and X5 E53 (00-06). In summary, the Vanos system is a critical feature in these engines, and understanding its operation is essential for maintaining these vehicles.
6-cylinder Double Vanos Procedure (E46, E39) has been experiencing a failure. Diagnoses indicate that the failure occurs due to the deterioration of the Vanos piston seal O-rings. As a result, the Vanos system loses efficiency over time.. Tests confirm that these O-rings consist of Buna (Buna-N, NBR, Nitrile), a common O-ring material with limited temperature and chemical resistance. Unfortunately it is fairing quite badly in the Vanos/engine environment. The O-rings have been found to harden, shrink, and have flat surfaces. The 6-cylinder Double Vanos Procedure deterioration causes the O-rings to lose their functional characteristics, thus leading to Vanos failure.
BMW has been contacted regarding this matter. However, they chose not to address the issue, stating, “No further development will be done.”. BMW does not provide the Vanos piston seals/O-rings as a separate part.
Here is a link to the Roadfly BMW E39 forum where much of this information was first made public: http://bimmer.roadfly.com/bmw/forums/e39/7494631-2.html
The piston O-rings lie under and provide support to piston Teflon seal rings. Replacing the O-rings requires removing the Teflon seals to access the O-rings. The Teflon seals can not be practically removed from the piston seal grooves without damaging them. Thus replacing the O-rings necessarily requires replacing the Teflon seals.
The Buna O-rings can be replaced with O-rings made from Viton. Viton (FKM, Fluorocarbon) has similar functional characteristics to Buna. Viton (FKM, Fluorocarbon) has similar functional characteristics to Buna. However, unlike Buna, it provides significantly higher temperature and chemical resistance. In addition , it is highly recommended for use in automobile engine environments. Moreover , this material ensures enhanced durability and longevity, making it a preferred choice for many applications. Therefore , when considering materials for high-stress environments, this option stands out due to its superior performance characteristics.
The Vanos Teflon (PTFE-filled) seals are not a standard part and, as a result, need to be semi-custom manufactured. Additionally, the 6-cylinder Double Vanos system features two pistons, each equipped with seals and O-rings. Specifically, each piston uses two seal/O-ring sizes to ensure proper hydraulic sealing in the two Vanos cylinders, which are of different sizes. This design allows the system to function efficiently and maintain optimal performance.
Each piston also utilizes one further small O-ring. 6-cylinder Double Vanos O-ring mounts on a small cap that’s used to seal off a piston bearing. The OEM O-ring for this cap seems to also be made from Buna and is deteriorating in the same manner as the piston seal O-rings.
A Vanos seals/O-rings repair kit can be acquired through Beisan Systems (bee-saan), www.beisansystems.com/products. It includes a Vanos replacement set of OEM material Teflon seals and enhanced (Viton) O-rings.
Here is a link to the Roadfly BMW E39 forum where the Vanos seals product was first introduced: http://bimmer.roadfly.com/bmw/forums/e39/8705552-2.html
Symptoms
Cars experience:
Overall loss of torque and power, particularly in the lower RPM range, < 3k. Bogging then surging at 3k RPM. Uneven power distribution and RPM transition. Engine hesitations in the lower RPM range, < 3k. Louder idle and intermittent idle RPM hiccups. Difficult takeoffs. Loss of power and bogging when AC on. Increased fuel consumption.
Repairing the Vanos seals provides:
Overall increase in torque and power, particularly in the lower RPM range, < 3k. Resolution of bogging then surging at 3k RPM. Smooth even distribution of power and RPM transition. Resolution of engine hesitations in the lower RPM range, < 3k. Quiet stable idle. Smooth easy takeoffs. Improved performance when AC on. Reduced fuel consumption, by ~10%.
Cars with the M52TU engine (98/99-00) experience cold weather cold start idle jolts and possible stall.
In some cases the engine computer will generate a fault code. The code is usually associated with the Vanos exhaust side. 6-cylinder Double Vanos is due to the powerful spring in the Vanos exhaust cylinder which forces the piston out. Fault codes include:
P1520 (BMW 104, 0x68): B (exhaust) Camshaft Position Actuator (faulty reference value).
P1523 (BMW 106, 0x6A): B (exhaust) Camshaft Position Actuator Tight or Jammed (mechanically stuck).
P1397 (BMW 18, 0x12): Camshaft Position Sensor B (exhaust) Circuit.
The exhaust camshaft position sensor (CPS) is a common failure. But if replacing the exhaust CPS (w/ OEM CPS) doesn’t work then it’s likely the Vanos failure.
On 01+ M54 & M56 engine cars codes P1520 & P1523 were removed. Thus code P1397 appears.
Diagnosis
With M52TU engine cars (98/99-00) with cold engine idle jolt symptoms, the Vanos intake solenoid (metal cylinder) electrical connector can be removed. If the idle jolts cease then the problem is the Vanos seals.
6-cylinder Double Vanos Procedure exhaust side fault code, as described above, is most likely a Vanos seals failure indication.
Otherwise the Vanos needs to be removed from the engine for inspection. Once the Vanos cylinder covers are removed, an inspection of the piston seals fit in the cylinders will show a loose fit and thus a seals failure. Removal of the seals from the pistons will show the inner O-rings have flat spots and a loss of elasticity.
In general, a diagnosis is not necessary. The Vanos Buna O-rings are deteriorating in 20k miles (32k kilometers). Thus essentially all the cars with this Vanos have deteriorated O-rings and a failing Vanos.
Repair Procedure
The following is an E46 & E39 double Vanos piston seals R&R (remove and replace) procedure.
If the valve cover gaskets have exceeded 40k miles (64k kilometers), it is advisable to replace them during this repair. Moreover, if they have surpassed 80k miles (128k kilometers), replacement becomes essential; otherwise, they may leak due to being dismounted and reused. Typically, these gaskets have an estimated lifespan of approximately 60k miles (96k kilometers). Additionally, replacing them during this repair requires no extra effort. The needed parts and replacement procedure are included as optional.
Regarding repair time, expect approximately 4 hours for a professional mechanic and 6+ hours for a DIY approach.
Parts, Tools, and Shop Supplies
When it comes to parts, those with the part number pattern xx-xx-x-xxx-xxx are genuine BMW parts and can be purchased directly from a BMW dealership. However, it’s important to note that Beisan Systems only provides the Vanos seals repair kit and does not supply other components.
Double Vanos seals repair kit (6-cyl) (BS001) $60/each (www.beisansystems.com), Vanos gasket (11-36-1-433-817) 6.73/each, 2 x Vanos oil hose/pipe washer (32-41-1-093-596) $.25/each
Optional Parts (6-cylinder Double Vanos)
M52TU & M54 Engines
For valve cover gasket replacement, you’ll need the following parts:
- Valve cover gasket set (< 09/02: 11-12-9-070-990, >= 09/02: 11-12-0-030-496) at $34.26 each
- 15 x valve cover bolt grommets (11-12-1-437-395) at $1.73 each
- Oil fill neck gasket (11-12-7-526-447) at $2.29 each
Additionally, be cautious with easily breakable parts:
- 2 x Vanos piston bolts (11-36-1-748-745) at $1.42 each
- 4 x engine cover bolt/nut caps (11-12-1-726-089) at $3.27 each
- Fan shroud rivets (17-11-1-712-963) at $0.27 each (E39: 2 required, E46: 1 required)
- Radiator overflow neck (E39 only: 17-11-0-419-132) at $1.67 each
Lastly, keep track of easily lost parts:
- 4 x engine cover pads (11-12-1-730-352) at $1.98 each
M56 Engine
For valve cover gasket replacement, gather these parts:
- Valve cover gasket sets (11-12-7-521-009) at 63.05eachand(11−12−7−521−010)at63.05eachand(11−12−7−521−010)at17.52 each
- 15 x valve cover bolt grommets (11-12-1-437-395) at $1.73 each
Similarly, be mindful of easily breakable parts:
Fan shroud rivet (17-11-1-712-963) at $0.27 each
E39: Small adjustable hose clamp. Needed if radiator overflow hose OEM clamp not previously replaced with adjustable clamp.
2 x Vanos piston bolts (11-36-1-748-745) at $1.42 each
Tools and Supplies
To begin, you’ll need the following tools for scraping and precision work:
- Gasket scraper or putty knife
- Straight pick tool, razor knife, and medium nose pliers (small, under 5 inches)
Next, gather the essential wrenches and screwdrivers:
- 19mm combo wrench
- Philips screwdriver (medium size)
- 3 flathead screwdrivers (2 medium, 1 small)
- Tack lifter and magnet pickup
For socket work, ensure you have the following:
- 13mm socket (1/2″) and a 3/8″ to 1/2″ socket adapter
- 13mm, 11mm, and 10mm sockets (3/8″)
- 8mm hex bit socket (3/8″)
- 8mm socket (1/4″), T30 and T25 torx bit sockets (1/4″)
- 3/8″ to 1/4″ socket adapter
Additionally, prepare the necessary ratchets and extensions:
- 1/2″, 3/8″, and 1/4″ ratchets
- 3/8″ long-arm ratchet
- 3/8″ and 1/4″ socket extensions (short)
Finally, don’t forget the torque wrenches for precise tightening:
Torque wrench (50 Nm [37 ft-lb])
Torque wrench (8 Nm [6 ft-lb])
Mechanical fan removal tools (not needed if electric fan):
First, ensure you have the following tools:
- 32mm combo wrench
- BMW water pump pulley holder (part number 11-5-030), priced at approximately $20 each
- Handheld sledgehammer (3lb)
Alternatively, you can purchase a Baum Tools water pump pulley holder or a holder and 32mm wrench combo. To find these items, visit the El Paso Tool store website and perform a “Store search” for “115030.” Make sure to check the “in titles & description” box to refine your search results.
El Paso Tool store
Paper towels, water based cleaner (simple green 1:10), spray lubricant, brake cleaner, engine oil (synthetic 5W30)
3Bond Drei Sealant (BS0SS) $19.90 (www.beisansystems.com), magic marker
Parts plate, small oil container, large cup
Not shown: large pad (quilt), oil pan, 3 small cloth towels, 2 grocery plastic bags
Repair
Car engine must be cold to perform repair procedure.
Right and Left denotations are from car front at hood orientation.
Removal of fan & shroud
E46 electric fan & shroud removal
E46 mechanical fan & shroud removal
Removal of cabin filter housing
E46 cabin filter housing removal
E39 cabin filter housing removal
Removal of valve cover
To begin, remove the engine top covers. First, pry off the 2 center caps located on each engine cover using a flathead screwdriver. Next, unscrew the 2 bolts on the right cover and the 2 nuts on the left cover using a 10mm socket, 3/8″ ratchet, extension, and magnet pickup. After that, remove the right engine cover. Then, unscrew the oil fill cap and take off the left engine cover. Finally, reinstall the oil fill cap to complete the process.
Start by removing the valve cover vent hose located at the front right corner of the cover. To do this, press in the hose connector ring clip at both the top and bottom, and then gently wiggle the connector off. Important warning: Avoid pulling the connector off directly, as this can cause a sudden release and potentially damage the hose. Instead, always wiggle the connector off carefully.
Moving on to the new design (04+): For O2 sensor fuel rail black bracket removal, follow the updated procedure.
Remove 2 O2 sensor cable brackets at fuel rail.
Press down on O2 sensor cable bracket and pry out of fuel rail slot.
Remove O2 sensor black cable bracket at fuel rail.
Pry off bracket clips on side of bracket and remove bracket from fuel rail (small flathead).
Old design coil / coil harness removal
Start by removing the ignition coils electrical harness. For each coil, pull up on the coil connector’s metal lock and then detach the cable electrical connector. After that, remove the coil harness ground wire from the valve cover bolt/stud located between coils 2 and 3 using an 8mm socket, 1/4″ ratchet, extension, and magnet pickup. If necessary, loosen the cylinder 3 coil mounting bolts to move the coil to the side, which will provide better access for tools.
Next, disconnect the coil harness rail from the valve cover clips. To do this, gently pry on each right-side clip using a flathead screwdriver and carefully pull out the coil harness rail. Once detached, remove the complete coil harness. For E46 models, place the coil harness on the intake manifold. For E39 models, set the coil harness on the strut tower.
Remove coils.
Unscrew 2 mounting bolts w/ washers at each coil (10mm socket 3/8″ / 3/8″ ratchet & extension). Note coil ground straps at coil 1 & 6.
Pull up and out all coils.
Note: Maintain coil/cylinder association for reinstallation. This is not necessary, but is good practice.
Remove coil ground straps at Cylinders 1 & 6 (8mm socket 1/4″ / 1/4″ ratchet & extension).
New design coil / coil harness removal
Remove ignition coils electrical harness.
For each coil, pull up and back on coil connector pivot lock until coil electric connector is thrust out and disconnected.
Remove coil harness ground wire from valve cover bolt/stud located between coils 2 & 3 (8mm socket 1/4″ / 1/4″ ratchet & extension, magnet pickup).
Note: Newest design coil harness has second ground wire between coils 4 & 5.
First, disconnect the coil harness rail from the valve cover clips. Next , pry on each clip located on the right side and pull out the coil harness rail using a flathead tool. Once the rail is free , pull off the complete coil harness. For E46 models , set the coil harness on the intake manifold. In contrast, for E39 models , set the coil harness on the strut tower.
Remove coils. Pull up and out all coils.
Note: Maintain coil/cylinder association for reinstallation. This is not necessary, but is good practice.
Start by removing the pre-cat O2 sensor electrical connectors and cables, as well as the secondary air valve vacuum hose, from the exhaust side valve cover brackets and metal clip. To do this , lift up on the metal clip tab to allow the cables to exit. Next , remove the electric boot and cables from the rear left bracket of the valve cover, as well as from the other rear brackets.
Note: If silver metal cover present at rear left bracket, lift up on cover tab to allow removing electric boot and cables without removing cover.
Remove 11 valve cover mounting bolts w/ washers & grommets at perimeter of valve cover (10mm socket 3/8″ / 3/8″ ratchet & extension, flathead).
Note: Be sure to not miss the rear left corner bolt.
Remove 4 valve cover mounting bolts/studs w/ washers & grommets at center of valve cover (10mm socket 3/8″ / 3/8″ ratchet & extension, flathead).
Note: On older models (99), third bolt/stud from front is same as the perimeter bolts. This is due to no ground connection at this location. Note this for reinstallation.
Remove valve cover from engine head.
Insert blade (putty-knife) between valve cover gasket and engine head at all front end accessible locations to break gasket bond. Be sure to break RTV sealant bond at sides of front half moon dips and Vanos/head matting points on each front side.
Pull up and remove valve cover. If resistant, insert blade (putty-knife) between valve cover gasket and engine head at sticking locations.
Note: If valve cover can not be removed, double check valve cover 11 perimeter bolts and 4 center bolts/studs have been removed. If valve cover is stuck, pull up on free front end of cover and right side vent pipe neck to break gasket bond on remainder of valve cover.
Pull up rear left cover cables to allow cover removal clearance.
Maintain valve cover perimeter gasket with cover.
Valve cover perimeter gasket will stick at rear half moon dips due to RTV sealant. Pull up on gasket to release.
Remove valve cover sparkplug well gaskets from engine head.
Note: If gasket is stuck to engine head, attempt inserting blade between gasket and head from an edge (putty-knife). This facilitates gasket removal without breaking plasticized brittle gaskets into pieces.
Removal of Vanos
Remove Vanos exhaust CPS (camshaft position sensor) electrical connector. Press in on side clips and pull off connector.
Note: If connector difficult to remove, pry out connector from end (tack lifter).
Remove Vanos exhaust solenoid electrical connector. Press in on metal clip and pull off connector.
Remove thermostat electrical connector. Press in on metal clip and pull off connector.
Remove Vanos intake solenoid electrical connector. Press in on metal clip and pull off connector.
Remove Vanos oil hose and bolt (19mm combo wrench).
Note: There are 2 washers, one at each side of hose end contact surfaces.
Discard washers.
Delete engine lift bracket at Vanos intake solenoid.
Erase top nut (11mm socket 3/8″ / 3/8″ ratchet & extension) and bottom bolt w/ washer (13mm socket 3/8″ / 3/8″ ratchet & extension).
Eliminate bracket. Rotate bracket bottom to top and then remove from top stud.
Remove 2 Vanos cylinder front cover bolts w /washers.
Cover AC belt and lower radiator hose to protect from oil leakage (towels).
Initially break bolt seize (tough), then place oil container below bolt and unscrew bolt (8mm hex bit socket 3/8″ / 3/8″ long-arm ratchet & extension).
Engine oil will leak out from Vanos cylinders. A significant amount will leak out from exhaust cylinder.
Stuff Vanos cylinders with cloth to extract engine oil (towels).
Clean up oil spills, especially from belts and pulleys.
Remove 2 Vanos piston caps (medium nose pliers).
Remove 2 Vanos piston / splined shaft mounting bolts; left hand thread (T30 torx bit socket 1/4″ / 1/4″ ratchet & extension, magnet pickup).
Note: Make sure tool is perfectly perpendicular to bolt when first breaking seize. This helps prevent bolt head stripping.
Note: Bolt is left hand thread, thus unscrew by turning wrench from left to right (clockwise) (car front orientation).
Note: If a bolt breaks, continue removal of Vanos from engine. Once Vanos is removed remaining bolt in splined shaft can be easily unthreaded (pick tool), left hand thread.
Begin by removing the six mounting nuts at the front lower half of the Vanos using a 10mm socket (3/8″ socket with a 3/8″ ratchet and extension). Next , remove the top right mounting bolt or stud of the Vanos using a 13mm socket (1/2″ socket with a 1/2″ ratchet). Note that a deep socket is required for this step.
Once the fasteners are removed , pull the Vanos forward off the head mounting studs and lift it out of the engine compartment. Before proceeding , cover the Vanos with double plastic bags, placing towels at the bottom to catch any spilling engine oil (grocery plastic bags and towels will work).
Afterward , take the Vanos to an oil receptacle and attempt to drain all the oil from it (use an oil pan). Tilt the Vanos to facilitate the drainage of oil from the cylinder covers, inner oil relief spouts, and outer oil feed access. Once drained , lay the Vanos down on a table with the inner side facing up.
Finally , remove and discard the Vanos gasket from the engine head. This step prepares the Vanos for the replacement of the piston seals.
During following seals installation procedure, great care should be taken to not drop and damage Vanos components. Perform work over table, so if part is dropped it will fall to table top. Vanos cylinder cover gaskets should also not be bent.
Note Vanos intake and exhaust orientation (picture: intake left, exhaust right).
Mark (magic marker) an “I” and “E” on the Vanos intake and exhaust pistons respectively to maintain piston to cylinder association. This is not necessary, but is good practice.
Note: Vanos intake and exhaust pistons are same part components and can be interchanged. Maintaining piston to cylinder association is good practice.
Remove Vanos cylinder covers. Remove bolts at each cover (10mm socket 3/8″ / 3/8″ ratchet & extension). Initially break each bolt seize, then unscrew the bolts.
Note: Exhaust side cylinder has spring behind piston that will force cylinder cover off during removal. Start by pushing down on the cover to facilitate bolt removal. Next , remove the pistons and exhaust-side spring from the Vanos cylinders. Once removed , drain the oil from the cylinders into an oil receptacle (such as an oil pan). Afterward , wipe off any remaining oil from the Vanos components using towels.
For diagnostic purposes , insert the pistons in and out of the Vanos cylinders (both the main body and covers) and note any loose fit. Then , inspect the Vanos cylinders (main body and covers) by feel for any signs of marring. The walls should be exceedingly smooth, with no irregularities that can be felt. Note that seal sliding wear patterns will be present, and the cylinder walls will not be as polished at the ends of the cylinders.
Finally , proceed with the removal of the piston seals. Two seal rings will be removed from each piston groove, for a total of four rings removed from each piston
Note: During seals removal, care should be taken not to nick piston groove rims.
For each piston perform following seals removal.
Cut cross section of piston large Teflon seal in piston groove (razor knife).
Note: Rocking of blade while pressing helps create cutting motion.
Remove cut Teflon seal from piston grove.
Cut cross section of piston large O-ring in piston groove (razor knife).
Note: Rocking of blade while pressing helps create cutting motion.
Remove cut O-ring from piston grove.
Cut cross section of piston small Teflon seal in piston groove (razor knife).
Note: Rocking of blade while pressing helps create cutting motion.
Remove cut Teflon seal from piston grove.
Cut cross section of piston small O-ring in piston groove (razor knife).
Note: Rocking of blade while pressing helps create cutting motion.
Remove cut O-ring from piston grove.
When seals removal is complete, piston grooves will have exposed metal with no seals.
Wipe clean piston grooves (towel).
Repeat seals removal for second piston.
Note: Deteriorated O-rings will be flattened at top and bottom surfaces, shrunk in size, and plasticized thus having a loss of elasticity. This is the common Vanos failure mode.
Piston seals installation
Before new seals installation, be sure four seal rings were removed from each piston, two from each groove, and piston grooves show exposed metal (above picture).
Two seal rings will be installed in each piston groove, total of four rings installed in each piston.
For each piston perform following seals installation.
Start by installing the small and large O-rings (circular brown) into their corresponding piston grooves. To do this , insert one end of the O-ring into the corresponding piston groove, and then stretch the other end over the piston, carefully dropping it into place using your hands or fingers. Once installed , verify that the O-ring is not twisted within the piston groove. If necessary , adjust and center the O-ring using a pick tool..
If Teflon seals in cold environment, < 70F (21C), soak seals in warm water for 2+ minutes.
Remove and dry Teflon seal just before installation.
Note: Perform following step on ground over large pad while kneeling with knees on pad. This minimizes risk of dropping piston and damaging its surfaces.
Begin by installing the small and large Teflon seals (rectangular black) into their corresponding piston grooves. To do this, insert one end of the Teflon seal into the groove and then stretch the other end over the piston, carefully dropping it into place using your hands or fingers. Be cautious not to overstretch the seals during this process.
Important notes:
While stretching, aim to distribute the tension evenly and avoid scuffing or damaging the seals. Some sliding of the seal on the piston rim is normal.
Keep in mind that moderate force is required to stretch the Teflon seals properly.
Once stretched and installed, Teflon seals will fit loosely in piston grooves.
Repeat seals installation for second piston.
Piston Teflon seals resizing
For each piston perform the following seals resizing.
Apply coat of assembly lubricant (engine oil) to Vanos intake cylinder wall. Be sure to include chamfer (rim bevel).
Apply coat of assembly lubricant (engine oil) to Vanos piston large Teflon seal and adjacent piston surfaces.
Insert piston large end into intake cylinder at ~60 degree angle, then rotate piston to insert into cylinder.
Rotate piston to be flush with cylinder. As piston is rotated, excess seal protruding from piston groove will be collected and pressed into piston groove.
Note: Be sure to rotate lower piston end up, so seal does not bind at cylinder bottom edge.
If seal is binding, reposition piston and attempt again. With each attempt seal will partially resized. Eventually piston can be fully rotated without binding seal.
Insert piston fully into cylinder to properly position piston.
Allow piston to sit in cylinder for 2 minutes then remove. Teflon seal will be compressed close to original size.
Apply coat of assembly lubricant (engine oil) to Vanos cover cylinder wall. Be sure to include chamfer (rim bevel).
Apply coat of assembly lubricant (engine oil) to Vanos piston small Teflon seal and adjacent piston surfaces.
Insert piston small end into cover cylinder inboard side. Insert piston with a slight tilt to cylinder. Excess seal will protrude from groove at tilted out end of piston groove.
Press protruding seal into piston groove and rotate piston to insert into cover cylinder.
If seal is binding, reposition piston and attempt again. With each attempt seal will partially resized. Eventually piston can be fully rotated without binding seal.
Insert piston fully into cover cylinder to properly position piston.
Allow piston to sit in cylinder for 2 minutes then remove. Teflon seal will be compressed close to original size.
First, verify that the piston Teflon seals have shrunk in size (resized) and are recessed into the piston grooves. Note: The Teflon seals may still protrude slightly (approximately 1mm) from the grooves, which is normal.
Next, repeat the Teflon seals resizing process for the second piston.
After resizing, apply a coat of assembly lubricant (engine oil) to all four Vanos cylinder walls. Make sure to include the chamfer (rim bevel) in this lubrication step.
Finally, clean the Vanos body and cover mating surfaces, as well as all cover bolts, using brake cleaner and towels.
Install pistons fully into Vanos cover cylinders. Install intake/exhaust pistons (previously marked) into associated covers. Intake side cover has 5 bolt holes and exhaust side cover has 4 bolt holes.
Note: Some alignment and effort will be necessary to reinsert pistons into cover cylinders.
Insert spring in exhaust cylinder.
Install cylinder covers w/ pistons onto corresponding Vanos cylinders.
On exhaust side, align spring to fit properly into Vanos cylinder spring groove and piston spring groove.
Mount cover bolts (10mm socket 3/8″ / 3/8″ ratchet & extension).
Note: Exhaust side has resistance due to spring. Push down on cylinder cover while mounting bolts. Mount bolts evenly to insert piston evenly.
Fully tighten, 10 Nm (7 ft-lb) (10mm socket 3/8″ / 3/8″ torque wrench & extension).
Note: Tighten bolts evenly in crisscross pattern.
Double check piston movement in Vanos cylinder by inserting piston in cylinder. Note: Exhaust side will need force to insert piston. Piston will spring out when force is released.
Remove 2 piston cap O-rings.
Cut cross section of cap O-ring in cap groove (razor knife).
Note: Rocking of blade while pressing helps create cutting motion.
Remove cut O-ring from cap.
Install 2 piston cap new O-rings (hands/fingers).
Note: O-ring should not be twisted during installation process.
Cleaning of parts
Note: When cleaning parts, spray cleaning compound on towel then wipe component with towel. Components can also be placed in a small container and sprayed with cleaning compound then individually wiped with towel.
Start by cleaning all mounting bolts/studs, nuts, washers, rubber grommets, and ground strap ends using brake cleaner and towels.
Next, clean the Vanos mating surfaces, including the head, valve cover, and oil feed, with brake cleaner and towels.
After that, remove any sealant compound from the engine head, specifically the Vanos joint and the front and rear half-moon corners, using a gasket scraper or fingernail.
Then, clean the coil mounting contact surfaces (at the coils) using brake cleaner and towels.
Proceed by removing the valve cover gaskets from the valve cover. Once removed, use a pick tool or fingernail to clear away any sealant residue on the valve cover gasket. Finally, clean the valve cover gaskets thoroughly using a water-based cleaner and towels.
Wipe down the valve cover mating surfaces, including gaskets and bolt access holes, with a water-based cleaner and towels.
Apply brake cleaner and towels to clean the engine head mating surfaces, focusing on the Vanos, Vanos studs, and valve cover gaskets.
Optional: Replacement of valve cover gaskets
Take out the valve cover gaskets and replace them with new ones.
Detach the valve cover oil fill cap. Next, replace the oil fill neck gasket with a new one. Mount valve cover oil fill cap.
Note: If oil fill neck gasket not present on valve cover, then gasket is likely of old design and can be fond on engine cover at oil fill hole. Remove old gasket from engine cover.
Note: If old gasket is stuck to valve cover, attempt inserting blade between gasket and cover starting from an edge (putty-knife). This facilitates gasket removal without breaking plasticized brittle gaskets into pieces.
Installation of Vanos
Mount new Vanos gasket onto engine head front. Mount top corners onto dowels and place gasket flush with head surface.
Note: Gasket is asymmetric.
Note: Fully insert Vanos intake piston into Vanos cylinder. This will simplify Vanos mounting to engine head.
Mount Vanos onto engine head front.
Insert Vanos onto engine head studs, then Vanos top corners onto head matting dowels. Fully insert Vanos to mate flush with engine head.
Begin by screwing on the 6 mounting nuts and the 1 stud/bolt located at the top right corner. To ensure even tightening, work back and forth across the nuts and bolt using a 10mm socket with a 3/8″ ratchet and extension, as well as a 13mm socket with a 1/2″ ratchet.
Once all nuts and the bolt are snug, fully tighten them to 8 Nm (6 ft-lb). Use a 10mm socket (3/8″) and a 13mm socket (1/2″) with a 3/8″ to 1/2″ socket adapter, along with a 3/8″ torque wrench and extension, to achieve the correct torque specification.
Note: Push Vanos intake (right) piston from cylinder hole until it mates with splined shaft (finger).
Install 2 Vanos piston / splined shaft mounting bolts; left hand thread (T30 torx bit socket 1/4″ / 1/4″ ratchet & extension).
CAUTION: Many torque wrenches cannot be used on left hand threads as the bolts will break!
Fully tighten, 8 Nm (6 ft-lb); left hand thread (T30 torx bit socket 1/4″ w/ 3/8″ to 1/4″ socket adapter / 3/8″ torque wrench & extension).
Install 2 Vanos piston caps w/ new O-rings (medium nose pliers).
Apply light coat of engine oil to cap O-rings to ease installation.
Rotate cap to verify full insertion.
Install 2 Vanos cylinder front cover bolts w/ washers (8mm hex bit socket 3/8″ / 3/8″ ratchet & extension).
Fully tighten, 50 Nm (37 ft-lb) (8mm hex bit socket 3/8″ / 3/8″ torque wrench & extension).
Note: Route electrical harness to engine side before mounting lift bracket.
Install engine lift bracket at Vanos intake solenoid.
Insert bracket top hole onto engine top stud, then rotate bracket down to front of thermostat.
Mount top nut (11mm socket 3/8″ / 3/8″ ratchet & extension) and bottom bolt w/ washer (13mm socket 3/8″ / 3/8″ ratchet & extension).
Fully tighten, 10 Nm (7 Ft-lb) (11mm socket 3/8″ & 13mm socket 3/8″ / 3/8″ torque wrench & extension)
Start by installing the Vanos oil hose with the bolt and 2 new washers using a 19mm combo wrench. To do this, mount the first washer onto the bolt, then insert the bolt through the hose. Next, place the second washer onto the bolt and screw the bolt into the Vanos.
Once the bolt is threaded in, fully tighten it to 32 Nm (24 ft-lb) using the 19mm combo wrench (or by feel if a torque wrench is not available).
Important note: To prevent the hose from turning during installation, insert a flathead screwdriver or rod between the hose pipe and the Vanos intake solenoid to hold it in place.
Important note: When routing the electrical cable for the exhaust CPS sensor and exhaust solenoid, ensure it runs behind the Vanos exhaust solenoid and valve. To secure it, insert the cable section with minimal electrical tape between the thermostat and Vanos, routing it toward the rear.
Next, connect the Vanos exhaust solenoid electrical connector. Then, attach the Vanos exhaust CPS sensor electrical connector. After that, secure the thermostat electrical connector. Finally, plug in the Vanos intake solenoid electrical connector.
Installation of Valve Cover
Place thin coat of 3Bond Drei sealant at 2 engine Vanos/head contact points, and at Vanos/head front and rear half moon corners.
Allow sealant to solidify for 2 minutes before mounting valve cover.
Install valve cover perimeter gasket and sparkplug well gaskets on valve cover.
Install valve cover onto engine head/Vanos. Take care to align properly before placement.
Lift up on rear corner hoses and cables to allow cover to fit under them.
Install 11 bolts w/ washers & grommets at cover perimeter, and 4 bolts/studs w/ washers & grommets at cover center (10mm socket 3/8″ / 3/8″ ratchet & extension).
Tighten bolts/studs evenly working back and forth, assuring even pressure distribution on cover. Tighten until bolts/studs bottom out on head.
Fully tighten, 8Nm (6 ft-lb) (10mm socket 3/8″ / 3/8″ torque wrench & extension).
Begin by installing the pre-cat O2 sensor electrical connectors and cables, as well as the secondary air valve vacuum hose, onto the valve cover exhaust side brackets and metal clip.
Next, route the cables and electric boot into the valve cover rear left corner bracket. Ensure proper alignment of the cables and hose into the valve cover bracket, and then install the electrical boot on top of the cables to secure them in place.
Note: If silver metal cover present at rear left bracket, lift up on cover tab to allow installing cables and electric boot without removing cover.
Install cables into valve cover rear brackets.
Old design coil / coil harness installation
Install coil ground straps at Cylinder 1 & 6 (8mm socket 1/4″ / 1/4″ ratchet & extension).
Note: Ground strap highly bent end mounts on valve cover stud. Cylinder 1 strap connector orients to top corner, and cylinder 6 strap connector orients to bottom corner. This facilitates alignment of strap loose ends to coil bolt mounts.
Install each coil into original sparkplug well and mount with 2 bolts w/ washers (10mm socket 3/8″ / 3/8″ ratchet & extension). Mount ground straps with coil 1 & 6 bolts. Rotate between coil mounting bolts to mount coil evenly.
Note: Coil boot will not fully insert onto sparkplug during initial mount. This is normal.
Fully tighten, 10Nm (7 ft-lb) (10mm socket 3/8″ / 3/8″ torque wrench & extension).
Install ignition coil electrical harness.
Install coil harness rail on valve cover and clip into place.
For each coil, lift up on connector metal lock, press in cable electrical connector, and push down on connector metal lock.
Install coil harness ground wire on valve cover bolt/stud located between coils 2 & 3 (8mm socket 1/4″ / 1/4″ ratchet & extension). Loosen cylinder 3 coil mounting bolts as needed to move coil to side to facilitate tool access. Retighten cylinder 3 coil mounting bolts.
New design coil / coil harness installation
Install each coil into original sparkplug well.
For each coil, orient coil tab to align with valve cover coil mating bracket, insert coil boot into sparkplug well, and press coil onto valve cover until fully seated.
Install ignition coil electrical harness.
Install coil harness rail on valve cover and clip into place.
For each coil, lift up on connector pivot lock, press in cable electrical connector, and push down on connector pivot lock.
Install coil harness ground wire on valve cover bolt/stud located between coils 2 & 3 (8mm socket 1/4″ / 1/4″ ratchet & extension).
Note: Newest design coil harness has second ground wire between coils 4 & 5.
New design (04+) O2 sensor fuel rail black bracket installation
Install O2 sensor black cable bracket onto fuel rail.
Press bracket onto fuel rail until all clips snap into place.
Install 2 O2 sensor cable brackets onto fuel rail.
Insert cable bracket into fuel rail slot and press down and in cable bracket to fully install.
Install valve cover vent hose at cover front right corner. Push hose connector onto cover neck until it snaps on.
Install engine covers.
Install right side engine cover. Mount cover right side hooks under fuel distribution rail. Install cover 2 bolts (10mm socket 3/8″ / 3/8″ ratchet & extension, magnet pickup).
Unscrew oil fill cap, install left side engine cover, reinstall oil fill cap.
Note: Push down on rear left corner electric boot to achieve proper cover fit.
Install 2 nuts at left side cover (10mm socket 3/8″ / 3/8″ ratchet & extension, magnet pickup).
Clip on 2 bolt/nut cover caps at center of each engine cover.
Align silver lines on cap with cover. Insert clip at an angle and gently press down on other end (picture).
Note: Caps are dry, brittle, and will break easily.
Installation of cabin filter housing
E46 cabin filter housing installation
E39 cabin filter housing installation
Installation of fan & shroud
E46 electric fan & shroud installation
E46 mechanical fan & shroud installation
Post repair procedures
Allow RTV sealant to dry a minimum of one hour before driving car.
On first engine start after repair the engine can experience a couple engine hiccups at idle. This might be related to trapped air in the Vanos.
Check and replenish engine oil.
Drive car, then park car and let engine oil settle.
Remove oil dipstick; wipe dipstick end; fully reinsert dipstick; remove dipstick again; read oil marking. If oil is low add needed (small) amount of new oil at oil fill cap at valve cover.
E39: Check and replenish coolant.
When car is fully cold (morning) open coolant expansion tank and check coolant level. Measuring sick top should be at expansion tank cap rim. Fill coolant as needed.
Drive car until warm. Slightly open each bleed screw and allow air to escape (Philips). Close bleed screw when only fluid is escaping. There is a bleed screw at the coolant expansion tank and a bleed screw at the radiator upper hose.
Repeat fill and bleed procedure as needed to achieve proper coolant level.
~200 miles (320 kilometers) of city driving is needed to fully break-in Vanos seals and achieve optimum performance. Spirited driving will hasten break-in period. Initial improvements will be felt in the first few days of driving.
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