2021–2024 GMC Sierra: 6.2L V8 engine knock or failure (L87)
Likely causes, ranked
- Connecting rod / crankshaft manufacturing defect (engine replaced under recall when inspection fails)$0–$0Shop
- Engine passes inspection (0W-40 oil, new filter and oil cap under recall)$0–$0Shop
Real-owner fix counts will appear here as reports come in.
DIY or shop: See DIY or shop section
Parts to check
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Symptom: Knocking or rattling from the bottom of the engine, low oil pressure, a check-engine light, rough running, or the engine shutting off while you drive. Some engines fail with no warning.
Likely causes
- Manufacturing defects in the connecting rods or crankshaft. GM recalled the 6.2L trucks and SUVs under 25V274.
- What the dealer does depends on your VIN. According to the recall documents, the dealer inspects the engine. If it passes, it gets 0W-40 oil, a new filter, and a new oil cap. If it fails, or it's in certain build ranges, the engine is replaced.
Cost
Free under the recall. GM-Trucks forum members point out that the thicker oil helps protect a healthy engine but won't repair one that's already damaged.
DIY or shop?
Dealer only.
Useful steps
- Look up your VIN on the NHTSA recall site now.
- If you hear a knock, stop driving and have the truck towed.
- After the recall, use the oil grade GM specifies.
Vehicle focus: 2021–2024 GMC Sierra.
Safety / mechanic note
An engine failure can mean a sudden loss of power at highway speed. Verify with a mechanic or dealer right away if your truck is covered by recall 25V274.
Recalls & service bulletins
Recalls
- 25V274000 2021–2024 Sierra 1500 and other GM full-size trucks/SUVs with the 6.2L V8: connecting rod and/or crankshaft defects can lead to engine failure. Details
NHTSA complaints: 521 keyword-matched complaints for GMC Sierra 1500 2021–2024 (of 2,036 total complaints queried, NHTSA complaints API by model year, queried 2026-10-15).
Always check your VIN for open recalls at nhtsa.gov/recalls.
Sources
What actually fixed it?
Had this problem? Tell other owners what the real fix was. Reports are counted above; we never show made-up numbers.