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SOURCE-BACKED RESEARCH PACK · EXECUTION BLOCKED

N43 coolant-thermostat replacement

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

Cold-engine safety, coolant handling, thermostat replacement and leak-check dependencies mapped without publishing historical values as current.

0/5 steps released · 1 linked source · about 60 minutes when released.

WHAT YOU WILL LEARNadvanced path

This page is intentionally useful before release: it exposes the repair map, sources and unresolved evidence. Mapped steps cannot be completed or mistaken for workshop instructions.

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.
APPLICABILITYSTEP 1 / 5
EVIDENCE MAPPEDcritical

Confirm exact vehicle and installed configuration

This research-stage item keeps the repair visible without presenting incomplete evidence as executable guidance.

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No visual needed for this step

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

Evidence mapped — workshop release blocked

This item is visible so the repair map is complete, but WrenchGuide will not let you execute or complete it yet.

  • Current BMW or licensed professional safety-critical specifications and replacement-hardware rules are not yet fully reconciled.
  • Current hose, seal, coolant and venting requirements remain unresolved.
  • Exact thermostat part and production split require VIN confirmation.
EVIDENCE MAP
  1. Map VIN/build/options and inspect the installed component before selecting parts.
LEARN AS YOU GO
  • A mapped source proves that material exists; it does not prove exact fitment, current specifications or a safe complete sequence.
TOOLS

No tools required for this step.

PARTS & SUPPLIES

No parts or supplies required for this step.

SOURCES & PROVENANCE1 linked

Legacy BMW TIS — 11 53 000 N43 coolant thermostat

BMW AG / Workshop-Manuals mirror · Source guide / procedure map · accessed 2026-08-13

vehicle manufacturer
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 exact vehicle and installed 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.