General Motors made an uncommon running update to its popular 2018 GMC Terrain and 2018 Chevrolet Equinox crossovers to bolster side-impact crash safety last year.
The update, which consumers won't be able to spot by looking at the crossovers' exteriors, was applied to 2018 GMC Terrains built after Nov. 28, 2017 and 2018 Chevrolet Equinox crossovers built after Feb. 19, March 5, or March 12, 2018, depending on assembly location.
The running update included additional welds and foam blocks placed in the rear driver- and passenger-side doors.
DON'T MISS: Read our full review of the 2018 Chevrolet Equinox
Federal testers initially scored the early models of the GMC Terrain and Chevrolet Equinox at three stars for crash safety for rear passengers, but later models earned a five-star rating. A three-star rating on the federal score means that the risk of serious injury is equal to or higher by one-third to the relative fleet average of 2008 model year vehicles. A five-star rating means that the risk of serious injury is reduced by a third or more.
A GMC spokesman confirmed the running update and said the additional safety measures weren't in place for the initial test, and the automaker requested a retest.
The relatively poor initial rating sunk the overall score for the Terrain and Equinox to four stars, which is relatively rare for new cars. The added welds and foam improved the rating to a five-star overall score.
Automakers rarely offer running updates to structural components to their vehicles due to the high cost of retooling for numerous vehicles.
A spokesman for the IIHS said that differences in the independent, insurance-industry funded tests meant that it wouldn't change its scores for the Terrain or Equinox. It's unclear how many early builds of the Equinox or the Terrain were sold without additional welds or foam blocks.