Mazda CX-90 Oil Change: Inline-Six and Plug-In Hybrid

The CX-90 replaced the CX-9 for 2024 and brought two new powertrains: a turbocharged 3.3-liter inline-six with a 48-volt mild-hybrid system, and a plug-in hybrid that pairs a 2.5-liter four with an electric motor. In the Carson Valley it is a three-row family hauler, the one doing the school run in Minden on weekdays and the climb to the lake on Saturdays. Both engines share one maintenance schedule, which makes the oil side simpler than the hardware suggests.

At a glance

• One U.S. schedule for both engines: maximum 10,000 miles or 12 months (2025 CX-90 scheduled maintenance)
• Severe driving: oil and filter every 5,000 miles or 6 months
• Mazda Canada's 2025 CX-90 schedule names Genuine Mazda GF-6 0W-20
• Inline-six spark plugs every 40,000 miles; PHEV plugs every 120,000 km (about 75,000 miles)

Two powertrains, one oil schedule

The 2025 CX-90 guide says the vehicle status monitor lights the wrench before 10,000 miles or 12 months after the previous service. Mazda's severe column moves the oil and filter to 5,000 miles or 6 months for long idling or low-speed use, mainly unpaved roads, or mainly mountain and uphill roads, and asks the owner to set that interval on the monitor manually.

Mazda Canada's 2025 CX-90 brochure, written for both the mild-hybrid inline-six and the plug-in hybrid, names Genuine Mazda GF-6 0W-20 as its engine oil. Mazda's own parts listing also names the e-Skyactiv 2.5 PHEV among the applications for its 0W-20 oil. We did not find a published fill quantity for either CX-90 engine, so we fill to the dipstick marks rather than to a number off a chart.

The plug-in hybrid and its 12-month limit

A CX-90 PHEV can run its daily errands on battery and start the gas engine only on longer trips. That is easy on oil mileage but not on the calendar, because the 12-month ceiling still applies. Engines that run rarely and in short bursts are exactly what Mazda's idling and low-speed condition describes.

The plug-in also has its own EV coolant loop: Mazda Canada lists it at 192,000 km or 15 years, then every 96,000 km or 5 years. Brake fluid is a special brake-by-wire type on the e-Skyactiv models, and Mazda schedules a brake fluid replacement every second service visit, so we check its level and leave the flush to the schedule.

Why Carson Valley driving fits the severe column

From our Gardnerville shop on US 395, the routes to Lake Tahoe are Kingsbury Grade and Spooner Summit on US 50, and both are long climbs. Mazda's own words, mainly mountain or uphill roads, describe a family that makes that drive every weekend. Douglas County households average 2.25 vehicles (ACS 2020-2024), and the CX-90 is often the one that gets the hard miles.

Minden also averages 188 nights a year at or below freezing (NOAA 1991-2020 normals), so a winter CX-90 that starts cold and runs short is a candidate for the 5,000-mile interval on two counts.

What we look at on a CX-90

• Oil at the grade on the cap, new filter, and the engine oil data reset Mazda requires after every change
• Engine air filter and cabin filter; Mazda replaces the cabin filter every 30,000 miles or 24 months
• Coolant level and condition (FL-22 for the engine), plus the PHEV's separate EV coolant reservoir
• 12-volt battery test, belts, lights, wipers and the pressure in all four tires
• Driveshaft boots and the underbody covers Mazda lists for inspection