Coolant-gate: Zoom-zoom goes boom-boom as Mazda faces a class action in the US

The defect affects Mazda's 2.5-litre Skyactiv-G engine in the CX-5, CX-9, Mazda6, and Mazda3. Allegation: coolant can leak into the engine oil, causing catastrophic engine failure at relatively low mileages — some as early as 60,000km. Repair cost: $8,000 to $15,000.

In Australia, Mazda has issued no recall and offered no assistance. If your oil looks like a cappuccino, stop driving the car immediately. Document everything. If your engine fails, don't accept "wear and tear" as an explanation.