GM bulletin 18-NA-150
What it saysThis informational bulletin provides information on 6.6L Duramax Possible Oil Leak Path Information. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Aug 15, 2024, received Oct 7, 2022, about the engine — 2 documents under this number. It names 37 model years across Chevrolet and GMC (2017–2025). 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 communicationWhat 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.
This informational bulletin provides information on 6.6L Duramax Possible Oil Leak Path Information.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 18-NA-150 | Service bulletin | Aug 15, 2024 | 11007430 | PDF, 624 KB |
| 18-NA-150 | Service bulletin | Sep 9, 2022 | 10222657 | PDF, 634 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 23 model years
Also filed against model years this site has no page for: 2019 Chevrolet 6500.
GMC 14 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 7,695 complaints with NHTSA since 2015. 2,430 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 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.
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
Engine hesitation, or misfiring. Jerking, or transmission shuttering when engine is at low RPM and on incline. (i.e. When traveling about 45mph and start up a hill, the rpm's are about 1300, and the transmission doesn't gear down, so it starts shuttering until you give it more acceleration than usual.) after dealing with this issue for…
2017 Chevrolet Silverado · Engine · filed with NHTSA Jul 18, 2018 · ODI 11112166
Multiple instances of diesel engine emissions system parts and software failure. While driving, towing or not, the DIC would randomly display a message that the DEF level is low and reduced speed will occur in x-amount of miles and that mileage would then begin a visible countdown on the DIC, sometimes much more quickly than the actual…
2021 GMC Sierra 3500HD · Engine · filed with NHTSA Nov 1, 2024 · ODI 11623109
In depth: 2025 Chevrolet Silverado engine problems → · 2024 Chevrolet Silverado engine problems → · 2023 Chevrolet Silverado engine problems → · 2022 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 group189 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… |
| 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… |
| 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… |
| 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… |
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 18-NA-150 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 18-NA-150 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 18-NA-150 cover?
The manufacturer filed it against 37 model years across 2 brands (Chevrolet and GMC): 2025 Chevrolet Silverado, 2024 Chevrolet Silverado, 2023 Chevrolet Silverado, 2022 Chevrolet Silverado, 2021 Chevrolet Silverado, 2020 Chevrolet Silverado and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.