Mazda Cx 9
Problems & Worst Years

A cracked cylinder head causing a coolant leak is the defining complaint of the 2018 CX-9, the only model year in this data, reported 36 times at high severity out of 80 total complaints. A related complaint — overheating and engine failure stemming from that same coolant leak — adds another 20 reports, meaning roughly 70 percent of this model year's complaints connect back to one underlying cooling problem. An infotainment screen cracking and malfunctioning contributes 12 more reports on a separate track, while two smaller but more serious complaints round out the top five: a brake system malfunction leading to unintended braking (4 reports) and a passenger seat heater malfunction described as leading to fire (4 reports), both carrying the dataset's safety-severity tag.

Two recall campaigns, 19V403 and 21V875, apply to the 2018 CX-9, and given how directly they likely relate to the coolant and cylinder head pattern dominating the complaint file, confirming both have been completed should be an early step in evaluating any used example. The seat heater fire complaint, while reported only 4 times, is serious enough that a buyer should also ask directly whether that repair has been addressed.

With only one model year represented and 7 total problem categories, this is a relatively narrow dataset, though the concentration around a single mechanical issue makes it easier to know what to check for. A cooling system inspection, along with confirmed recall completion, would tell a buyer more about a specific vehicle's condition than the complaint count alone — and as always, these are owner-filed reports rather than a certified failure rate, with any single model year's total shaped partly by how long it has had on the road, so documented service history deserves real weight in the decision.