N55 Valve Cover Replacement

On the N55 the valve cover is more than a lid. The wastegate vacuum reservoir (a vacuum tank) and the PCV valve are part of it.

Not for ActiveHybrid 3, 5 or 7L. BMW's repair text for them starts with high-voltage safety steps.

Is it the valve cover?

  • Oil at the cover edge, burning smell. BMW's leak bulletin: a light oil film from sweating needs no repair. A medium to large buildup with pooling, dripping and spotting is an active leak.
  • Rule out the cheap stuff. One owner thread blames a loose lower left screw. Oil filter housing leaks get blamed on the cover too: see the oil filter housing gasket guide.
  • Whistle at idle, or code 28A0 or 101F01. Owners say the whistle stops when you loosen the oil filler cap a little. BMW uses the same trick: noise gone means crankcase pressure.

BMW's order for those codes: after new software or a battery reset, the adaptation first, before replacing parts (unplug the tank vent valve connector, idle 15 minutes, plug it back in, clear faults, test drive). Then a smoke test (shop gear). Smoke from the reservoir's hose stubs with both wastegate vacuum hoses off means a micro-crack in the cover. BMW says the engine computer is not the fix.

Myth check: the N55 has no eccentric shaft sensor on the valve cover. BMW built it into the Valvetronic motor. The cover carries the intake camshaft sensor.

Gasket only, or the whole cover?

  • Gasket set only if the cover is whole and the leak is at the gasket.
  • Whole cover if it's cracked or the whistle or codes point at the PCV side. BMW sells no PCV part alone.

Same teardown either way, and you need the flange seal and screws below. BMW sells the gasket set separately: check your cover's listing.

The parts

Fits these N55 cars, by chassis code (unsure? Send us your VIN): E82/E88 135i, E90/E92 335i and 335xi, E93/F30 335i, F34 335i GT, F32/F33/F36 435i, F22/F23 M235i, F87 M2, F10 535i, F07 535i GT, F06/F12/F13 640i, F01/F02 740i and 740Li, E84 X1 xDrive35i, F25 X3 35i, F26 X4 35i, E70/F15 X5 35i, E71/F16 X6 35i. N55 only: 135i and 335i built from 03/2010, 740i and 740Li from 07/2012 (earlier ones are N54).

11 12 7 570 292The valve cover for every N55 on that list, vacuum reservoir built in.
Cover gasket setBMW 11 12 7 587 804One outer seal, 11 12 7 576 308, and three inner seals, 11 12 7 576 309.
Valvetronic flange sealBMW 11 37 7 502 022Two screws, 11 36 7 609 963, go with it. Some BMW repair versions say renew the seal, none says reuse. Shop rule of thumb, not BMW's: new seal and screws every time.

The vent hose often breaks. Buy it first.

Owners on F2x and F3x cars report snapped hoses and tabs. Your number depends on your chassis code and the blow-by heater, a heater on the crankcase vent (BMW: standard on US cars).

BMW 11 12 7 599 753F30, F32, F33, F34, F36, F22, F23, F87.
BMW 11 12 7 584 128F07, F10, F25, F26, E70, E71. Also E82, E88, E90, E92, E93, E84 if the car has the blow-by heater (check by VIN).
Genuine $69.99 →Burgaflex $58.99 →
BMW 11 12 7 590 163F01 LCI, F02 LCI (facelift cars; pre-LCI? Send us your VIN). Also E82, E88, E90, E92, E93, E84 if the car has no blow-by heater.Genuine $61.99 →
F06, F12, F13, F15, F16Either number, by build date and heater. Send us your VIN and we'll send yours.

Some sellers list 11 15 7 559 528 as an N55 vent hose. BMW's catalog doesn't fit it to US N55 cars: skip it.

Worth doing while it's apart

Spark plugs and coils12 12 0 037 582 (Bosch) fits most of the cars above. The F87 M2 and the X4 M40i (F26, built 12/2015 to 03/2018) take 12 12 0 039 634. Delphi coils: 12 13 8 616 153 (six). Check by VIN, or see the spark plug guide.
Bosch plug $18.99 →NGK plug $24.99 →Coil $42.99 →Coils and Bosch plugs $366.99 →Coils and NGK plugs $397.99 →

How long it takes

Plan on a full day. Owners report about 4.5 hours on an M235i, about 7 hours of work (11 start to finish) on a first F30 job.

Figure 1All 26 cover screws and BMW's tightening order, 1 and 2 first. The steps that use it are below.

Tools

  • Sockets and wrenches: E12 (cover screws) and E6 (flange screws); 8 mm (coil ground screws), 10 mm, 16 mm, T30; a flexible extension and universal joint for the rear screws; a 14 mm flare nut wrench or crow's-foot for the fuel line nuts; a torque wrench that reads low (8.5 Nm is low for many).
  • Also: face guard, gloves, fuel container, caps for open fuel connections, magnet on a stick, inspection mirror, picks for hose tabs, glass cleaner, transmission oil, a scan tool that reads BMW fault codes (28A0 and 101F01 are BMW codes).
Battery and fuel first. Negative battery terminal off (work the clamp off, don't lever it) before any harness, fuel line or positive cable work: a short can start a fire, and opening a door can wake the fuel pump. Fuel work only with the coolant below 40 °C (104 °F).
Coolant. BMW's cover job doesn't drain coolant. Pulled a coolant hose anyway? Engine fully cold first (hot coolant scalds), new coolant only, then fill and bleed per the expansion tank guide.

Removal order, by car

Map 1, every N55: what BMW has you remove

  1. Negative battery terminal
  2. Cowl and body itemsA cowl panel cover or a right-side "trailing link". BMW doesn't say which cars get which.
  3. Air pipe or duct
  4. Coil cover and coils
  5. Pressure (fuel) lines
  6. Wiring harness
  7. Valvetronic flangenew seal, 2 new screws
  8. Vacuum line
  9. Vent linenew hose on hand
  10. Cover screws
  11. The valve covernew gaskets

Map 2, E82 E88 E90 E92 E93 only: what else comes off first (one E92 owner, not BMW)

  1. Wiper arm, cabin filter, cowl
  2. The whole intake
  3. Strut bars and firewall panelStrut bar bolts: one-time use (owners). No BMW torque.
  4. Cowl weatherstrip, engine cover wires, engine cover
  5. ECU box opened, harness unplugged
  6. All six coils, injector wiring
  7. Vacuum and PCV hoses
  8. Fuel rail and lines
  9. Cover screws, then the cover
F30, F32, F33, F34, F36, F22, F23Owner threads: metal oil lines from the oil filter housing are in the way: pull them aside slowly. F22 rear screws, bottom left worst, are very hard to see. The back left screw and the one under the oil lines need a universal joint.
F25 X3, F26 X4A vendor write-up removes a crossover brace (two 16 mm bolts).
F15 X5, F16 X6An owner says the bottom passenger side rear screw must go in straight or it wedges.

Torque

8.5 NmAll 26 cover screws (6.3 ft-lb).

Steps

Cover off means the engine is open. Cams, rockers and oil drains are right there. One dropped screw, rag thread or plastic chip can wreck the cylinder head. Count tools and rags in and out, lay a clean cloth over the head whenever you step away, and tape every open port. No key, no cranking, and don't touch the cams or the Valvetronic shaft (shop rules, not BMW's).

Out

  1. Engine cold, negative battery terminal off.
  2. Cowl and body items, then air pipe or duct, off, per your map or maps.
    Figure 2The cowl panel at the base of the windshield, held along its edge. Generic layout: yours may differ.
    Figure 3The clean air pipe (3): undo the two hose clamps (1) and the sensor plug (2). Generic layout: yours may differ.
  3. Coil cover and coils off, a cloth in each spark plug well. Pull each coil slowly straight up. Never oil or grease the coil boot (it's talc-coated). It can tear, and fuel damages it.
    Figure 4The cable channel over the coils, held by screws at each end. Generic layout: yours may differ.
  4. Fuel lines off, each marked with its cylinder. Face guard and gloves on. No flame nearby, extinguisher in reach (shop rule). Wipe each fitting clean before it opens. Tap the injector under a rag if pressure needs bleeding. Release each line at the fuel rail first, then the injector, catching the fuel in a container. Keep fuel out of the plug wells: it ruins the coil boots. Plug the rail port, the injector port and both ends of every line straight away, and keep the rubber mounts. Lines can be re-screwed at most 10 times.
    Figure 5A high pressure line (1), its nuts at each end (2) and its rubber mount (3). Rail end first when it comes off. Generic layout: yours may differ.
  5. Wiring harness off around the cover. Photograph each plug and hose first. Brittle connector tabs (owners): open each lock fully, use a pick, don't pry.
  6. Flange off: two screws (E6), then the Valvetronic flange. Old seal and screws go in the bin.
    Figure 6The Valvetronic flange (2) and its two screws (1). New seal and new screws on the way back. Generic layout: yours may differ.
  7. Vacuum line off, at the reservoir on the cover. Press and hold its unlock tab toward the arrow, then lift the line off. Two lines? Tape-label A and B.
    Figure 7The vacuum line (1) on the reservoir: press the unlock collar where the arrows point, then lift the line straight up. Generic layout: yours may differ.
  8. Vent line stays on the cover; unscrew its intake end. BMW says don't loosen it at the cover. Owners say one screw holds it, but BMW gives no count: look at yours.
    Figure 8The engine vent line: leave it on the cover (1), undo its screw at the intake end (2). Generic layout: yours may differ.
  9. Cover screws out, outer edge toward the middle, until 26 sit on your board. Half a turn at a time. Two are hidden at the rear (owners): under-count and the cover won't lift. Lay them in order, they differ in length. Cover won't lift? A screw is still in: look, never pry. A screw that spins without tightening or snaps: stop, and never swap in a longer one.
  10. Cover out: lift and rotate it toward the driver's side, then forward (owner tip). Pulling straight forward broke a PCV oil drain off one E90 cover, and it fell between two rocker arms.

In

  1. Whole-cover job: old and new cover side by side. Move across anything the new one lacks (we have no full list), such as the intake camshaft sensor and the oil filler cap unless your kit has one (11 12 8 655 331). Gasket-only job: skip to In step 3.
  2. Vent hose on the new cover. To replace a faulty one, BMW says break open the coupling at the old cover. To reuse the old one, owners open at least three tabs at once with several picks and spray glass cleaner under the hose. Either way, push it on until every tab clicks, then tug it to check.
  3. Head face clean, nothing inside. Wipe the head's sealing face and the cover's groove with a lint-free cloth, no scraper. Check the dowel pins and the plug wells, and that no wire, hose or clip sits on the sealing face. Owners say a sharp edge at the top rear of a camshaft can cut the gasket. Something snapped off or fell in? Stop. The cover doesn't go on until it's out: magnet, light, mirror. A piece left inside can wreck the head (shop rule, not BMW's).
  4. New gaskets in the groove, cover down flat. Gaskets (BMW: replace all) can fall out or roll. Lower the cover from the driver's side (owners), gently: the PCV oil drain underneath is fragile. Mirror-check the seals before tightening.
  5. All 26 screws, in BMW's order, 8.5 Nm each. Each screw back in the hole it came from. First start all 26 by hand, about half a turn each: every screw caught, none tight. Then torque in the numbered order on the drawing: screw 1 first, then screw 2 (they locate the cover), then 3 to 26 in number order. Out of order, the plastic cover can warp and leak. Don't have the order in front of you? Stop and send us your VIN. Don't guess.
    Figure 9BMW's tightening order for the 26 cover screws: 1 and 2 first (red), then 3 to 26 in number order. Redrawn from BMW's N55 figure.
  6. Vent line and vacuum line back, then the Valvetronic flange with a new seal and two new screws, run in by hand until the flange sits flat. Torx-head screws (what we always find): 5.5 Nm. Hex-head screws: 10 Nm. Our shop's numbers: BMW's N55 cover text gives none. No power tools.
  7. Fuel lines back, each to its own cylinder with its rubber mount, a little transmission oil on the thread and the ball end. Both nuts must spin on by hand. One fights you? Stop: a forced nut leaks at full rail pressure. BMW's fix: loosen that line's nuts and the hold-down screws, fit the lines hand-tight, hold-down screws 13 Nm ± 1, then the nuts. Torque the injector nut first, then the rail nut. Lines from the rail to the injectors (M12 nuts): 23 Nm ± 3. The line from the high pressure pump to the rail (M14 nuts), if you opened it: 30 Nm ± 3. Fuel rail to head, if it came off: 13 Nm ± 1. Keep a crow's-foot at 90 degrees to the torque wrench (owners; no BMW correction figure).
  8. Spark plug wells blown clean, coils in, then the rest of your map backwards. Coil cover 4 Nm, its metal bracket 8 Nm, coil ground screws 5 Nm. Wiring channel screws on the cover: BMW's tables disagree, send us your VIN. If the whole intake came off: new intake gaskets (BMW: replace all), plenum nuts and M7 screw 15 Nm, gaiter clamp 3 Nm.
  9. Before the first start: every fuel nut torqued, no fuel-wet rags left in the bay, plug wells dry. Then negative terminal on, start. BMW ends with a fuel leak check: light and mirror on every opened line, never a hand near a line with the engine running. Any wet nut: shut off and fix it before the car moves. Check the oil level at operating temperature. A 28A0 or 101F01 light means the 15 minute adaptation first (see above). Still there after it? Check your own work first: the vent hose, the vacuum line and a pinched gasket.
Leave the Valvetronic motor alone. The cover job doesn't need it off, and BMW's job for it carries spring preload and shaft kickback warnings.

Where people mess it up

  • Dropping debris into the head. Bolts go down the injector wells and manifold: magnet, covers on every opening. Anything lost inside: the cover stays off until it's found.
  • Torquing the cover out of order. 1, then 2, then 3 to 26, from the drawing.
  • Forcing a fuel line nut. Both nuts spin on by hand or you stop.
  • Overtightening. Owners build torque in passes: finger tight, snug, final. They say too tight leaks the gasket, and a vendor warns these are aluminum screws in plastic.

Steps, torque values and part rules come from BMW's repair instructions for the cylinder head cover, the ignition coils and the high pressure fuel lines. Part numbers come from BMW's parts catalog up to 2020. Check yours by VIN.

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