2018 model year · 3,250+ owner reports · Updated April 2026
According to Au7o's analysis of 3,250+ owner reports, the 2018 Mazda CX-9 has 4 documented known issues. No issues are rated critical, indicating generally reliable ownership. The most commonly reported issue is Transfer Case Fluid Leak (AWD Models) with 1,600 owner reports. Across all issues, repair costs range from $150 to $2,000. DIY maintenance guides at au7o.io.
On the 2007-2023 Mazda CX-9, aWD-equipped CX-9 models develop fluid leaks from the power transfer unit (PTU) / transfer case. The output shaft seal and case halves are common leak points. Low fluid levels lead to increased wear, whining noises, and eventual transfer case failure. Fluid changes are not part of the standard maintenance schedule, which allows undetected deterioration.
Replace PTU output shaft seal and refill with Mazda FE-LS ATF. If internals are worn, PTU replacement is required. Proactive fluid changes every 30,000 miles significantly extend PTU life.
Parts and tips from 1,600+ owners who fixed this issue
On the 2016-2023 Mazda CX-9 2.5L SkyActiv-G Turbo, the 2.5L turbo engine in second-generation CX-9 develops coolant leaks from the turbocharger coolant supply and return lines. Heat cycling causes the connection points and hoses to deteriorate. Low coolant levels can lead to turbo damage and engine overheating if not caught early.
Replace turbo coolant supply and return hoses with updated parts. Inspect turbo oil lines and intercooler connections at the same time. Mazda revised the hose material for better heat resistance in later production.
Parts and tips from 900+ owners who fixed this issue
On the 2016-2025 Mazda CX-9, the second-generation CX-9 with the 2.5L turbocharged SkyActiv-G engine can develop timing chain stretch, producing a rattle or whine at startup that may persist for several seconds. Unlike the first-gen 3.7L V6 issue, the 2.5T chain stretch is typically less severe but still requires attention. The issue is linked to extended oil change intervals and use of non-synthetic oil allowing chain guide and tensioner wear.
Use full synthetic 0W-20 oil and change at 5,000-mile intervals (not the 7,500-10,000 Mazda suggests for normal driving). If chain rattle is present, the timing chain, tensioner, and guides should be replaced. Mazda has issued TSBs for software updates to address cold-start rattle in some model years. Inspect during valve cover gasket or cam seal service.
Parts and tips from 0+ owners who fixed this issue
On the 2016-2023 Mazda CX-9, the power liftgate system fails to open, close, or hold position. Causes include liftgate strut motors wearing out, latch mechanism failure, and wiring harness damage in the rubber boot between body and liftgate. Cold weather exacerbates the issue as struts lose gas pressure.
Replace power liftgate strut motors (sold as a pair). Check and repair wiring harness in the liftgate rubber boot for broken wires. Replace latch mechanism if liftgate does not latch properly.
Parts and tips from 750+ owners who fixed this issue
SEATS:MID/REAR ASSEMBLY
Mazda North American Operations (Mazda) is recalling certain 2020-2021 CX-9 vehicles equipped with 60/40 split bench second-row seats. The left-side second-row seat may unexpectedly slide forward during a crash. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 210, "Seat Belt Assembly Anchorages."
Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.
Don't see your problem? Describe your symptoms to get a diagnosis, or get a full repair guide.
According to Au7o's analysis of 3,250+ owner reports, the 2018-2018 Mazda CX-9 has 4 documented issues. The most frequently reported are: Transfer Case Fluid Leak (AWD Models), Turbocharger Coolant Line Leak, Timing Chain Stretch and Rattle (2.5L Turbo SkyActiv). None are rated critical, but regular maintenance is recommended.
The 2018-2018 Mazda CX-9 has 4 known issues documented across 3,250+ owner reports. No issues are rated critical, suggesting generally good reliability. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Mazda CX-9 issues range from $150 to $2,000, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
AWD-equipped CX-9 models develop fluid leaks from the power transfer unit (PTU) / transfer case. The output shaft seal and case halves are common leak points. Low fluid levels lead to increased wear, whining noises, and eventual transfer case failure. Fluid changes are not part o… Repairs typically run $150-$2,000. Severity: medium.
The 2.5L turbo engine in second-generation CX-9 develops coolant leaks from the turbocharger coolant supply and return lines. Heat cycling causes the connection points and hoses to deteriorate. Low coolant levels can lead to turbo damage and engine overheating if not caught early… Repairs typically run $200-$600. Severity: medium.
The second-generation CX-9 with the 2.5L turbocharged SkyActiv-G engine can develop timing chain stretch, producing a rattle or whine at startup that may persist for several seconds. Unlike the first-gen 3.7L V6 issue, the 2.5T chain stretch is typically less severe but still req… Repairs typically run $800-$2,000. Severity: medium.
The power liftgate system fails to open, close, or hold position. Causes include liftgate strut motors wearing out, latch mechanism failure, and wiring harness damage in the rubber boot between body and liftgate. Cold weather exacerbates the issue as struts lose gas pressure. Repairs typically run $300-$900. Severity: low.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
