Nissan’s variable compression engines have caught the attention of U.S. safety regulators, following multiple reports of alleged engine failure, loss of power, engine knocking, and metal chunks and shavings being found in oil pans.
The automaker’s 1.5-liter KR15DDT, three-cylinder, and 2.0-liter KR20DDET inline-four engines are the units under investigation. They power certain Nissan Rogues, Altimas, and Infiniti QX50s. In all, the National Highway Traffic Safety Administration (NHTSA) estimates that the engines can be found in a total of 454,840 vehicles.
While discussing the issue with Nissan, NHTSA discovered that the automaker was aware of the engine’s flaws. In fact, it introduced multiple manufacturing process changes over the lifetime of the units in an attempt to address damage to the main bearing and L-link, which could lead to seizing.
Under Investigation
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The engines in question feature variable compression technology, which has a multi-link system that varies the pistons’ top dead and bottom dead center positions in order to change the compression ratio. This allows the ECU to dynamically control the engine based on circumstance and offers power and efficiency advantages.
Neither the automaker nor NHTSA have yet specified the root cause of the problem, but since the latter is interested in only these engines, it seems plausible that the novel variable compression system is to blame, at least partially.
However, NHTSA has not yet found a reason to compel Nissan to launch a recall campaign. Instead, it has opened a preliminary evaluation into the concern to assess its scope, frequency, and safety consequences. Based on the results of its probe, it may then call on Nissan to launch a recall.