BMW bulletin B640426
What it saysCustomer may feel something transmitted via the steering column while turning the steering wheel. NHTSA’s full summary ↓
BMW filed this with NHTSA as a service bulletin dated Jun 27, 2026, received Jul 3, 2026, about the engine. It names 1 model year (2023). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationWhat it applies to, as the document itself states it — the build window in the manufacturer’s own words, read by machine from the PDF NHTSA serves. The build date is on the certification label in the driver’s door jamb; the dealer settles a borderline vehicle by its VIN.
Customer may feel something transmitted via the steering column while turning the steering wheel. There may also be coolant lost accompanied by a check control message: ‘Top up coolant’.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| B640426 | Service bulletin | Jun 27, 2026 | 11034465 | PDF, 521 KB |
What the document itself lists
Parts the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 64 21 8 846 463 | Coolant Hose, supply | — | eBay Motors → |
| 83 19 2 468 442 | Antifreeze/Coolant (DN = 1 Gallon Concentrate) - HT-12 As needed | — | eBay Motors → |
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 64 99 000 | WT to re-reposition the coolant hose after accessing (Loosen hose clamp and rotate… | 1 FRU |
Read by machine from the document NHTSA serves (8 pages), read Sep 30, 2026. A part number is shown only where it matches BMW’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 1 model year this bulletin names have filed 10 complaints with NHTSA since 2015. 3 of them name Engine — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
I own a 2023 BMW 530i affected by NHTSA recall campaign 26V-438 (BMW "Engine Starter" recall), issued July 8, 2026. Per BMW's own recall documentation, unexpected wear on an internal starter component can cause the starter to malfunction and, in an extreme case, cause a thermal event or fire when starting the engine OR while the engine…
2023 BMW 5 Series · Engine · filed with NHTSA Jul 25, 2026 · ODI 11752807
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group26 other manufacturer communications filed against the BMW 5 Series under the same component group (engine), newest first. The eight newest are listed; the rest are on the BMW list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 0012870600 | Service campaign | Oct 10, 2026 | Due to an implementation error in various OBD diagnostics in the vehicle's control units, in very rare cases itmay happen that stored fault… |
| 1171901000 | Warranty extension | Sep 22, 2026 | The Exhaust Gas Recirculation (EGR) Cooler (with EGR Valve) and the Auxiliary Exhaust Gas Recirculation (EGR) Cooler limited warranty for de… |
| B121126 | Service bulletin | Sep 9, 2026 | Potential customer complaints with no fault codes stored / No MIL displayed. 1. “Rough idle after idling for a longer period of time” 2. “Ve… |
| 1613911200 | Warranty extension | Aug 3, 2026 | the NVLD modules limited warranty for defects in materials and/or workmanship has been extended to 15 years / 150,000 miles as determined fr… |
| B063926 | Other | Jul 13, 2026 | Starter Generator Return |
| 0099020300 | Emissions | Jul 10, 2026 | Due to an implementation error in various OBD diagnostics in the vehicle's control units, in very rare cases itmay happen that stored fault… |
| 1390900300 | Warranty extension | Jun 29, 2026 | For this vehicle, the EVAP systems purge (vent) valve limited warranty for defects in materials or workmanship has been extended to 15 years… |
| B111025 | Service bulletin | Dec 12, 2025 | Coolant is leaking from the oil filter housing. |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for BMW, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is BMW B640426 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the B640426 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every BMW warranty extension on file lists the ones BMW has filed.
Which vehicles does B640426 cover?
The manufacturer filed it against 1 model year: 2023 BMW 5 Series. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone. The document itself sets the build window: built on or after 30 Jun 2023 — the build date is on the certification label in the driver’s door jamb.