all vehicles · every Sierra year · method

GMC Sierra 2021

Safety complaints filed by owners in the first three years, per 1,000 sold.

0.45 per 1,000

0.9 times this nameplate’s own median · from 113 complaints filed in the first three years, of 657 ever. 95% lower bound 0.37.

Against its own model years

The model year carries far more information than the badge, so this is the comparison that matters.

Model year	Per 1,000	Complaints
2008	0.23	38
2009	0.19	27
2010	0.13	16
2011	0.24	33
2012	0.16	25
2013	0.19	33
2014	1.33	264
2015	1.13	247
2016	0.41	92
2017	0.52	114
2018	0.48	106
2019	0.80	181
2020	0.58	141
2021	0.45	113
2022	0.73	178
2023	1.22	328

What owners describe

Phrases over-represented in these complaints compared with the same component on every other vehicle. Counts are complaints containing the phrase.

Engine 327 complaints

truck	132	40%
valve	52	16%
lifter	44	14%
lifters	43	13%
control valve	41	13%
coolant control	34	11%

Power Train 162 complaints

truck	69	42%
valve	40	25%
control valve	21	13%
reduced	16	10%
diesel	15	9%
valve body	14	9%

Electrical System 85 complaints

truck

40%

When it breaks

28% of reported failures happened before 30,000 miles (median 51,248 miles, from 141 complaints that recorded one).

Failures arrive late and spread out, which looks like wear. Service history matters more than model year here.

What NHTSA did

5 investigations covering this model year, 1 of which list a recall campaign.

Loss of motive power due to engine failure

What owners and forums say

Not built yet. This panel is meant to carry community sentiment beside the filed-complaint data, so the two can be compared. Showing something weaker here would defeat its purpose.

Check this yourself

Example records behind this page:

11378245 · 11378394 · 11383585 · 11388759 · 11396897 · 11396939

Limits of this figure. It counts safety complaints filed with the federal government, which is a floor on failures and not a census: problems that only cost money are under-reported. Complaint rates also reflect how likely a brand’s owners are to file, which cannot be separated from how often the car fails. Sales are calendar-year and the denominator for this nameplate is automated checks only, not verified against an external source.