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RESEARCH PREVIEW · EVIDENCE-GATED

N43B20 engine replacement

BMW 3 Series Touring · E91 LCI · 320i · N43B20 · Manual

Released preparation steps can be completed; mapped and review-stage engine work stays locked until exact safety data, parts, tools and validation criteria clear review.

REFERENCE VISUALS

Reference media is kept separate from step photography so a useful image cannot accidentally masquerade as exact procedure guidance.

BMW N43B20 engine bay photographed in a 2010 BMW E88 convertibleENGINE-FAMILY REFERENCE

N43B20 engine-bay reference

Real N43B20 engine-family reference. This photograph is from a 2010 BMW E88, not an E91, so it must not be used as a routing, fastener-location or step-by-step reference for the E91 pilot.

ApplicabilityEngine family matches N43B20; vehicle chassis does not match the E91 pilot.
Phosmux / Wikimedia CommonsCC BY 4.0

FASTENER PLAN

Know what must be replaced before you start

WrenchGuide tracks fastener material, reuse policy and tightening specification separately. A torque-plus-angle instruction does not automatically mean a fastener is torque-to-yield or single-use; the replacement rule must be verified independently.

0mapped fasteners
No verified fastener map is published for this procedure yet.

WrenchGuide will not guess whether a bolt is aluminium, reusable, torque-to-yield or replace-after-removal, and it will not invent a torque value. Exact vehicle, engine, transmission and drivetrain applicability can change the answer.

Replacement rule and tightening method are different facts.WrenchGuide only labels a fastener replace-after-removal, aluminium or torque-to-yield when the applicable evidence supports that exact statement. Torque + angle is shown as a tightening method, not used as proof of torque-to-yield by itself.

BEFORE YOU START

Parts, tools & supplies

WrenchGuide builds this list from the repair itself. Mandatory items only become hard requirements after their need has verified provenance.

100%Verified requirements still being assembled
Job inventory pending technical verification.

The procedure can exist before its complete shopping/tool list does; WrenchGuide will not invent parts just to make this panel look complete.

Fitment and approval are separate checks.An OEM/reference number narrows a part search and an oil viscosity narrows a fluid search, but neither replaces the verified vehicle fitment or manufacturer approval. Production date, VIN, engine/transmission, installed hardware and current product data can still matter.
PREPARESTEP 1 / 11
WORKSHOP RELEASEDcritical

Confirm the vehicle configuration

+
No visual needed for this step

Follow the written checks and use the linked sources when you need more context.

Critical safety step

Read the entire step, including every stop condition, before marking it complete.

DO THIS~5 min
  1. Confirm the guide matches the vehicle before using any procedure-specific instruction.
  2. Record the VIN, production date, engine identification and transmission configuration for applicability checks.
  3. Stop if the vehicle configuration differs from this procedure.
TOOLS

No tools required for this step.

PARTS & SUPPLIES

No parts or supplies required for this step.

Progress saved locally on this device.

MY WORKSHOP JOURNAL

Remember how your car came apart.

Attach private notes and your own teardown photos to the exact procedure step. They stay on this device in the current local-first beta.

NOTESAuto-saved locally

Confirm the vehicle configuration

MY PHOTOS0 / 6
Image only · up to 12 MB each
No personal photos for this step yet.

Take a quick photo before disconnecting or removing something you may need to identify during reassembly.