GM bulletin 19-NA-256
What it saysThis service bulletin provides diagnostic aid information/procedures to perform inspections to determine if the engine needs to be replaced as opposed to just internal parts for knocking, rattle, squeak and/or squeal… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Nov 29, 2023, received Apr 12, 2023, about the engine — 2 documents under this number. It names 56 model years across Chevrolet and GMC (2016–2024). 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 service bulletin provides diagnostic aid information/procedures to perform inspections to determine if the engine needs to be replaced as opposed to just internal parts for knocking, rattle, squeak and/or squeal type noises from engine.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 19-NA-256 | Service bulletin | Nov 29, 2023 | 10246483 | PDF, 335 KB |
| 19-NA-256 | Service bulletin | Mar 15, 2023 | 10234106 | PDF, 335 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.
Model years it names
Source: as the manufacturer filed themChevrolet 38 model years
GMC 18 model years
and 10 more on this site: 2016 GMC Acadia, 2022 GMC Canyon, 2021 GMC Canyon, 2020 GMC Canyon, 2019 GMC Canyon, 2018 GMC Canyon, 2017 GMC Canyon, 2016 GMC Canyon, 2017 GMC Terrain, 2016 GMC Terrain.
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 56 model years this bulletin names have filed 8,934 complaints with NHTSA since 2015. 1,795 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.
On the 2016 Chevrolet Equinox, the 78 owners who gave an odometer reading for Engine reported it at a median of 88,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
Transmission slipped almost from start. Took three appointments and two years - If my shop foreman knew the third time, why did he not call and tell me we now know your problem. I finally got fed up and brought it in one more time. Starter from day ONE maybe 50% of time made loud bang when Bendix retracted. Shop refused to take it off!!!
2018 GMC Canyon · Engine · filed with NHTSA Jan 1, 2022 · ODI 11445813
GM had a recall on the 3.6 lgz equipped in trucks in canada. Cold weather caused oil pump to over pressurizing of oil and damage to oil cooler and lines. Leaking oil in to engine compartment and on roadway. This has happened to me twice now once in march of 2018 and now again in november 2019. Doing research this is a common complaint.
2017 GMC Canyon · Engine · filed with NHTSA Nov 20, 2019 · ODI 11281338
I was driving on express way 96W Left lane busy 5 o'clock traffic Car just died it was stop n go I could have been killed if it wasn't for a man that stopped behind me he couldn't help another person stopped and push the car in N To a grass area where at least I wouldn't be smashed in Called 911 state police inform help van He didn't…
2020 Chevrolet Blazer · Engine · filed with NHTSA Oct 25, 2023 · ODI 11551752
In depth: 2020 Chevrolet Blazer engine problems → · 2016 Chevrolet Colorado engine problems → · 2017 Chevrolet Equinox engine problems → · 2016 Chevrolet Equinox 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 group170 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 |
|---|---|---|---|
| N262566800 | Service campaign | Oct 20, 2026 | Certain vehicles listed above may have a condition in which the incorrect transmission parts were used. Dealers will replace the transmissio… |
| N262570770-03 | Service campaign | Oct 16, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are t… |
| N262570770-02 | Service campaign | Sep 25, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| N262570770-01 | Service campaign | Sep 18, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| N262570770 | Service campaign | Sep 15, 2026 | Certain vehicles may have a condition in which the thermal break tabs induce stress into the radiator causing a coolant leak. Dealers are to… |
| 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… |
| N262546590-01 | Service campaign | Jul 15, 2026 | Certain vehicles listed above, may have a condition where coolant leaks from the radiator hose quick connect at the radiator inlet. This sp… |
| N252540910 | Service campaign | Feb 25, 2026 | Service Update. Certain vehicles listed above may have a condition in which a quality issue with the engine was identified. Dealers will re… |
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 19-NA-256 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 19-NA-256 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 19-NA-256 cover?
The manufacturer filed it against 56 model years across 2 brands (Chevrolet and GMC): 2024 Chevrolet Blazer, 2023 Chevrolet Blazer, 2022 Chevrolet Blazer, 2021 Chevrolet Blazer, 2020 Chevrolet Blazer, 2019 Chevrolet Blazer and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.