NHTSA opens a safety probe affecting nearly 900K GM vehicles

Although it is not officially a full-blown recall, the National Highway Traffic Safety Administration (NHTSA) opened a new safety probe on January 16th, 2025, looking into multiple General Motors brands that span five model years and a total of 877,710 potentially affected vehicles.

The NHTSA’s Office of Defects Investigation received 39 complaints about engines failing with no signs of advanced warning or prior symptoms. Along with these complaints, the ODI used corroborating field reports that point to similar engine failures as the cause of accidents and damage.

At the figurative and literal heart of the matter is General Motors’ relatively new L87 V-8 engine. A typical straightforward modern GM small block, the L87 is a 6.2-liter naturally-aspirated overhead valve engine that uses direct fuel injection and makes a robust 420 horsepower and 460 pound-feet of torque.

The L87 uses a stout forged steel crankshaft, but connecting rod bearing caps that are made of cheaper cast nodular iron. Unlike stronger cast forged or cast steel, cast nodular iron can be highly susceptible to surface defects and cracking due to micro-shrinkage pores. These defects can lead to the failing connecting rod bearings, which can, in turn, result in massive engine failure with almost no notice.

If the NHTSA’s ODI determines that these bearings are, in fact, the root cause of the engine failures. In that case, it will then issue an official recall notice via its website and notify all owners of potentially affected vehicles.

The list of affected brands, models, and years is as follows: