2021 Mazda CX-30: What to check before buying

Oil disappears between changes with no visible leak. The low oil warning often appears well before the next service, sometimes as early as 4,600 miles, and the dipstick shows about a quart low. Some report adding a quart every 1,500 miles. Several reports involve the 2.5-liter turbo. Dealers often confirm there is no leak, call the consumption normal, or cite a service bulletin with no fix. Owners worry the engine could seize while driving.

The battery goes flat without warning, and the car won't start until it gets a jump. Owners describe repeat drains, replaced batteries that die again, and repeated dealer visits where the cause is never found. Some cars lose power at low speed with a 12-volt charge warning on the dash. In one case the engine stalled at 65 mph with engine and computer malfunction messages. Smaller complaints include a display or USB that cuts out and a noise from the headlight.

Wavy, distorted windshield glass is the main complaint. Drivers report eye strain, headaches, and fatigue on long drives, plus poor night visibility and trouble judging distance. Some buyers notice it within days of purchase. Replacement windshields often show the same distortion, and dealers say Mazda calls some distortion normal for this design. Other reports describe a tiny chip spreading into a long crack and sunroof glass that shattered outward at highway speed.

Sudden acceleration while parking or shifting gears is the most serious pattern here. Drivers press the brake, the car fails to stop, and it hits a pillar or nearby objects. This category includes 3 crash reports and 1 injury. Other complaints describe automatic braking that slams on with nothing ahead, causing a neck injury, and a Critical Brake System Malfunction message at 22,000 miles. Fast rear brake wear also appears.

Transmission failures can cut acceleration or make the car surge and slow down in bursts at highway speed, then leave it unable to move. Engine and transmission warning lights may come on only after the problem starts. One car ran rough with an engine malfunction light, and the dealer blamed a corroded wiring harness before calling for a new transmission. The rest of these reports repeat other problems: oil consumption, dead batteries, and random lock, liftgate, and alarm behavior.

The car speeds up without the driver pressing hard on the gas, sometimes while parking, and the brakes fail to stop it. Reports include 2 crashes and 1 injury, one at about 1,000 miles. Adaptive cruise control can surge hard once the car ahead moves out of the lane, sometimes revving to 3500-4000 rpm. One report pairs a lunge and hesitation with a transmission error and a stuck shift solenoid code.

Emergency braking kicks in with nothing in the way, and the car can skid to a stop in a live traffic lane. Drivers say only distance from the car behind prevented a rear-end crash. One crash report with 4 injuries says cruise control did not disengage when the brake was pressed approaching a light. Insects on the front sensor came up in one false-braking report.

Airbags fail to deploy in serious side and corner impacts. Both reports are crashes, with 3 injuries between them. In one, the side airbags on the struck passenger side stayed off while the driver side deployed. In the other, the frontal airbags stayed off when the car was hit broadside. Both vehicles were totaled. No warning lights were reported beforehand.