GM service campaign N232430450
What it saysOn certain vehicles, equipped with a 6.6L diesel engine (RPO L5P), the engine coolant may have become contaminated. NHTSA’s full summary ↓
GM filed this with NHTSA as a service campaign dated Aug 14, 2024, about the engine. It names 4 model years across Chevrolet and GMC (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.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationPicked out of NHTSA’s summary below, word for word. The document itself is the record, and the dealer checks the VIN.
What it applies to, as NHTSA’s summary states it — build dates and equipment as the manufacturer filed them. The dealer checks the VIN and the build date on the door jamb; a vehicle outside the window is not covered by this bulletin.
Service Update. On certain vehicles, equipped with a 6.6L diesel engine (RPO L5P), the engine coolant may have become contaminated. Dealers are to inspect the radiator surge tank. If contamination is visible, dealers are to order the required parts and schedule the customer for another appointment to perform the repair.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| N232430450 | Service campaign | Aug 14, 2024 | 11006368 | PDF, 151 KB |
What the document itself lists
The manufacturer titles it “N232430450 - Service Update”.
Parts the bulletin names
| Part number | Description | Qty |
|---|---|---|
| 12346290 | — | — |
| 10953464 | — | — |
| 19435229 | — | — |
| 86771839 | Surge Tank | — |
| 85119145 | Heater Outlet Hose | — |
| 85119164 | Heater Inlet Hose | — |
| 85122989 | Radiator Inlet Hose | — |
| 85119169 | Radiator Outlet Hose | — |
| 85584374 | Radiator Surge Tank Inlet Hose | — |
| 85119168 | Radiator Surge Tank Outlet Hose | — |
| 85119162 | Engine Coolant Air Bleed Hose | — |
| 12695930 | Engine Coolant Air Bleed Pipe | — |
Read by machine from the document NHTSA serves (5 pages), read Sep 30, 2026. A part number is shown only where it matches GM’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 themChevrolet 2 model years
GMC 2 model years
A 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 4 model years this bulletin names have filed 356 complaints with NHTSA since 2015. 35 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.
The contact owned a 2024 GMC Sierra 2500 HD. The contact stated that after parking the vehicle at night and plugging in the engine block heater to a standard 110-Volt outlet with an extension cord; 15-minutes later neighbors were screaming to the contact to exit the residence because the vehicle had caught on fire, and the residence was…
2024 GMC Sierra 2500HD · Engine · filed with NHTSA Nov 25, 2024 · ODI 11627201
The contact owns a 2024 Chevrolet Silverado 2500. The contact stated that while starting the vehicle, the check engine warning light illuminated. The vehicle was taken to the dealer, where the battery was disconnected temporarily to reset the ECM. The check engine warning light was reset; however, the failure reoccurred while driving.
2024 Chevrolet Silverado 2500HD · Engine · filed with NHTSA Nov 29, 2023 · ODI 11557393
The contact owns a 2024 GMC Sierra 3500. The contact stated that while driving at various speeds, there was an abnormal knocking sound coming from the vehicle. There were no warning lights illuminated. The vehicle was taken to a local dealer where it was diagnosed; however, the cause of the failure was not yet determined.
2024 GMC Sierra 3500HD · Engine · filed with NHTSA May 1, 2025 · ODI 11658087
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 group89 other manufacturer communications filed against these GM models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N262572131-01 | Service campaign | Oct 23, 2026 | Customer Satisfaction Program. Certain vehicles listed above may have a condition in which the oil galley in the cylinder head was not dril… |
| N262572131 | Service campaign | Aug 28, 2026 | Customer Satisfaction Program. Certain vehicles listed above may have a condition in which the oil galley in the cylinder head was not dril… |
| 25-NA-339 | Service bulletin | Nov 6, 2025 | Under Field Actions N252494000, N252494001, the service procedure includes performing a PICO test on vehicle engines within the identified s… |
| 22-NA-080 | Service bulletin | Sep 6, 2025 | This technical bulletin provides a procedure to replace the camshaft actuator magnet to correct customer concerns of engine related shudder. |
| 25-NA-150 | Service bulletin | Jun 5, 2025 | This bulletin provides a procedure to check and replace the oil cooler seals before just replacing the oil cooler, for an oil leak. |
| 00-06-01-026R | Service bulletin | Jun 5, 2025 | This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage. |
| 23-NA-170 | Service bulletin | May 16, 2025 | This bulletin advises the tech to inspect deeper into what may be the main cause of an engine failure. |
| 23-NA-153 | Service bulletin | May 15, 2025 | The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet and GMC, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM N232430450 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 N232430450 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 N232430450 cover?
The manufacturer filed it against 4 model years across 2 brands (Chevrolet and GMC): 2024 Chevrolet Silverado 2500HD, 2024 Chevrolet Silverado 3500HD, 2024 GMC Sierra 2500HD, 2024 GMC Sierra 3500HD. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.