BMW service campaign B640724
What it saysQuality checks have determined that the coolant changeover valve may develop a coolant leak under ver ylow outside temperatures (significantly lower than 32º F (0 C)). NHTSA’s full summary ↓
BMW filed this with NHTSA as a service campaign dated May 24, 2024, received May 29, 2024, about the engine. It names 2 model years (2023–2024). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
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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.
Quality checks have determined that the coolant changeover valve may develop a coolant leak under ver ylow outside temperatures (significantly lower than 32º F (0 C)).
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| B640724 | Service campaign | May 24, 2024 | 11000514 | PDF, 163 KB |
What the document itself lists
Parts the bulletin names
| Part number | Description | Qty |
|---|---|---|
| 64 11 9 462 114 | Changeover valve | 2 |
| 07 11 9 906 123 | Hexagon screw with washer | 2 |
| 31 11 6 899 302 | Multi-purpose bolt | 14 |
| 61 27 9 487 465 | Screw | 1 |
Read by machine from the document NHTSA serves (4 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.
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 2 model years this bulletin names have filed 72 complaints with NHTSA since 2015.
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 group5 other manufacturer communications filed against the BMW iX under the same component group (engine), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| B640326 | Service bulletin | May 7, 2026 | After starting up the vehicle, a distinct, constant, “humming” noise can be heard from the right area of the instrument panel. |
| B170124 | Service bulletin | Feb 25, 2026 | There is coolant leaking from under the car Low heater output Possible Check Control message “Drive, you can continue driving” (ID49) Pos… |
| 0064340200 | Service campaign | Dec 9, 2024 | Quality checks have determined that the coolant changeover valve may develop a coolant leak under verylow outside temperatures… |
| 0064290200 | Service campaign | Jul 11, 2024 | Quality checks have determined that the coolant changeover valve may develop a coolant leak under very low outside temperatures… |
| B640324 | Service bulletin | May 23, 2024 | The coolant changeover valve may develop a coolant leak when the outside temperatures go below 19°F (-7°C). The vehicles operating systems… |
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 B640724 a recall?
No. A service campaign 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 B640724 repair free?
A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does B640724 cover?
The manufacturer filed it against 2 model years: 2024 BMW iX, 2023 BMW iX. 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: 2024 BMW: built 16 Mar 2023 – 12 Jan 2024; i20 iX Sports Activity Vehicle: built 16 Mar 2023 – 12 Jan 2024; that were produced: built 16 Mar 2023 – 12 Jan 2024 — the build date is on the certification label in the driver’s door jamb.