Mazda is responsible for one of the biggest reliability cock-ups in modern automotive history. A lot of Americans are not aware of this because this generation of diesel motor didn't make it to the American market but for many years they sold cars with a diesel engine with multiple critical manufacturing and design issues that resulted in thousands and thousands of defective engines. In many markets this was never recalled and at least in some markets Mazda's response was to draw another line higher up on diesel dipsticks so the owner could monitor if their crankcase was filling up with diesel, which would eventually dilute the engine oil and destroy the turbo and other components.

In my country used car dealers will not touch Mazda diesels for trade-ins because they always come back to them with destroyed engines.