GM bulletin 20-NA-024
What it saysThis service bulletin provides a information and diagnostic steps/tips for vehicles that are slow to heat up in cold temperatures. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 30, 2024, received Feb 14, 2024, about the equipment. It names 37 model years across Chevrolet and Buick (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 · Buick.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides a information and diagnostic steps/tips for vehicles that are slow to heat up in cold temperatures.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 20-NA-024 | Service bulletin | Jan 30, 2024 | 10250272 | PDF, 501 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 27 model years
Also filed against model years this site has no page for: 2023 Chevrolet Trax.
Buick 10 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 36 model years this bulletin names have filed 2,668 complaints with NHTSA since 2015. 862 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 Cruze, the 61 owners who gave an odometer reading for Engine reported it at a median of 66,445 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
Dear GM Executive Office, I am writing in frustration and disappointment after being told today by Chevrolet Customer Assistance that the case I opened (Case # ) was simply a "dealer complaint" and that no further help would be offered - despite my vehicle exhibiting a recurring, safety-related malfunction covered under Special Coverage…
2018 Chevrolet Sonic · Engine · filed with NHTSA Jul 22, 2025 · ODI 11675305
The contact owns a 2016 Buick Encore. While driving 65 MPH, the vehicle decelerated to 44 MPH and the vehicle stalled. The vehicle coasted until it came to a complete stop. The vehicle was restarted, but hesitated to drive. The vehicle was taken to bob ruth ford (700 n u.s. The vehicle was currently being repaired under warranty.
2016 Buick Encore · Engine · filed with NHTSA Oct 24, 2019 · ODI 11270668
The contact owns a 2016 Chevrolet Cruze. While driving the vehicle, the "start, stop" feature was activated when the contact approached a red light. When the accelerator pedal was applied while making a right turn, the vehicle lost power and was almost struck by another vehicle from the rear. The failure recurred multiple times.
2016 Chevrolet Cruze · Engine · filed with NHTSA Dec 2, 2016 · ODI 10929617
In depth: 2017 Chevrolet Cruze engine problems → · 2016 Chevrolet Cruze engine problems → · 2024 Chevrolet Trax 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 equipment
Source: same model, same component group58 other manufacturer communications filed against these GM models under the same component group (equipment), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| PIP5601B | Service bulletin | Jul 18, 2025 | This Preliminary Information communication provides information to the technician about vibration complaints that are one of the most challe… |
| 17-NA-073 | Service bulletin | Mar 5, 2025 | This warranty administration bulletin provides policy information with the field action courtesy transportation policy. |
| 17-NA-331 | Service bulletin | Jan 17, 2025 | Rear View Camera Guidelines Not Present at Times Condition Some customers may report that the Rear View Camera (RVC) guidelines are temp… |
| 22-NA-038 | Service bulletin | Dec 14, 2024 | This warranty bulletin provides information on Customer Concern Not Duplicated (CCND) Labor Operation Numbers. |
| 18-NA-263 | Service bulletin | Dec 14, 2024 | This warranty administration bulletin provides policy information for variable diagnostic time allowances on select labor operations… |
| 24-NA-040 | Service bulletin | Oct 11, 2024 | This service bulletin provides information on All hazmat parts being returned to the Warranty Parts Center (WPC) must be shipped using Centr… |
| 23-NA-154 | Service bulletin | Oct 2, 2024 | This bulletin provides information on Warranty Administration â Required Operating Procedures - 8 Points (U.S. Only). |
| 23-NA-219 | Service bulletin | Sep 21, 2024 | This service bulletin provides information on Concerns or Questions Regarding Installation of Dealer Installed Accessories. |
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 Buick, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 20-NA-024 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 20-NA-024 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 20-NA-024 cover?
The manufacturer filed it against 37 model years across 2 brands (Chevrolet and Buick): 2024 Buick Encore, 2023 Buick Encore, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2019 Buick Encore and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.