GM bulletin 24-NA-186
What it saysThis bulletin advises the tech that if the wrong mounts are installed, this may be the cause of the engine vibration. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Sep 12, 2024, received Oct 22, 2024, about the engine. It names 8 model years across Chevrolet and GMC (2019–2022). 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.
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 communicationThis bulletin advises the tech that if the wrong mounts are installed, this may be the cause of the engine vibration.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 24-NA-186 | Service bulletin | Sep 12, 2024 | 11009032 | PDF, 165 KB |
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.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
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Model years it names
Source: as the manufacturer filed themChevrolet 4 model years
GMC 4 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 8 model years this bulletin names have filed 5,746 complaints with NHTSA since 2015. 2,812 of them name Engine, Structure — 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.
On the 2019 Chevrolet Silverado, the 143 owners who gave an odometer reading for Engine reported it at a median of 71,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
While driving on the highway my truck started to buck and had a loud engine knocking noise. Speed was greatly reduced so much so that I was going under 45 mph in a posted 65. The check engine light did not come on. While sitting on the side of the highway there was a severe engine knock only when the revs on the engine were increased.
2021 GMC Sierra · Engine · filed with NHTSA Sep 9, 2021 · ODI 11432369
i FEEL IT IS IN THE FUEL MANAGEMENT SYSTEM When driving along every now and then you can feel a vibration like diving on rumble strips. there is no rhyme or reason for it. I had it to the dealer and they told me that was normal, if you don't want it to do it then drive in 9th gear. I'm not going to shift to 9th every time I drive
2022 GMC Sierra · Engine · filed with NHTSA Jan 3, 2023 · ODI 11499958
The contact owned a 2020 GMC Sierra Denali. The contact stated that while the vehicle was parked, there was an abnormal knocking sound coming from the engine compartment. The check engine warning light was intermittently illuminated. The vehicle was taken to a dealer; however, the cause of the failure was not yet determined.
2020 GMC Sierra · Engine · filed with NHTSA Sep 11, 2026 · ODI 11763621
In depth: 2022 Chevrolet Silverado engine problems → · 2021 Chevrolet Silverado engine problems → · 2020 Chevrolet Silverado engine problems → · 2019 Chevrolet Silverado engine problems →
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 group162 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 |
|---|---|---|---|
| N262576260 | Service campaign | Oct 15, 2026 | General Motors has decided to conduct a Voluntary Emission Recall. Certain vehicles may have a condition that could cause a small exhaust le… |
| N262568830 | Service campaign | Aug 4, 2026 | Certain vehicles listed above may have a condition in which the oil filter was not adequately tightened. Dealers are to check and tighten th… |
| N262548050 | Service campaign | Apr 24, 2026 | Certain vehicles, may have a condition that could cause the Catalytic Converter to fail. If this failure occurs, the Malfunction Indicator L… |
| N252494003-02 | Service campaign | Jan 21, 2026 | Certain vehicles listed above, may have a condition where the connecting rod and/or crankshaft engine components in these vehicles may have… |
| 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… |
| N252508341 | Service campaign | Sep 16, 2025 | Certain vehicles listed above, may have a condition that could cause the engine coolant control valve to fail an onboard vehicle diagnostic… |
| N252508340 | Service campaign | Sep 16, 2025 | Certain vehicles may have a condition that could cause the engine coolant control valve to fail. If this condition were to occur, the Malfun… |
| 24-NA-241 | Service bulletin | Sep 6, 2025 | This informational bulletin advises the technician of a part number change for long block engines used in the trucks noted. |
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 24-NA-186 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 24-NA-186 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 GM warranty extension on file lists the ones GM has filed.
Which vehicles does 24-NA-186 cover?
The manufacturer filed it against 8 model years across 2 brands (Chevrolet and GMC): 2022 Chevrolet Silverado, 2021 Chevrolet Silverado, 2020 Chevrolet Silverado, 2019 Chevrolet Silverado, 2022 GMC Sierra, 2021 GMC Sierra and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.