Off Topic Nissan engine failures

“ODI is launching a preliminary investigation based on six reports of engine failure“

So after hundreds of Mazda engine failure, what is needed for ODI to look into the Mazdas 2.5T engine?

ODI = US Office of Defects Investigation (ODI) . Have we been complaining to the wrong place all along?
I think the biggest difference in how the Nissan engine failures are treated compared to the Mazda ones lies in the nature of the failure. The cylinder head crack issues on the 2.5T and 2.5 NA typically start with slow leaks and progress from there. You'd get warnings or see symptoms before you'd see a sudden loss of power. It sounds like the Nissan engine failures typically result in more immediate failures, which make them more likely to experience a sudden loss of power or complete engine failure. Same reason the HLA issue on the 2.5NA resulted in a recall - HLA failure would result in the engine suddenly going into limp mode.

Number of potentially affected vehicles is likely also a factor, with their best selling car and SUV both included in the investigation, plus two other models from their Infiniti line.
Well, this is great news as we currently have a Rogue as a rental while the CX-50 is in the shop awaiting repairs from a minor accident. My wife will really be pissed if the Rogue leaves her stranded, she hated driving it before she even sat behind the wheel. haha

Side question, when one files a complaint with the NHTSA, is it reviewed by the ODI division or do further steps need to be taken? Asking as there was a recent investigation into the 2019 Jeep Compass engine shutting down due to a coolant temperature too high warning light. Ours started exhibiting this back in October but has never shut down while driving. It simply won't start initially but then will after waiting a couple of minutes. The NHTSA closed their investigation after FCA declared that it was not an unreasonable risk to safety as the vehicle warns the driver prior to shutting the engine off. *All* the driver has to do is put the car in park, re-start and carry on with no ill-effects to the drivetrain.
The key difference is whether the said defect could cause safety issue to consumers.
You would be surprised what do, and what don't.
Cracked engine block does not warrant a recall, but a pre-mature malfunctioning stop light does (yes, on a Prius I used to own).
A sudden movement of power seat warrants a recall, but a bad belt tensioner does not.
Safety concern is what triggers a recall.

I had a '98 BMW 540 with numerous issues/defects. Never one single recall.