This SA supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-061/25 12/17/25 DESCRIPTION If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s) stored...), interview the customer before proceeding with normal MGSS diagnosis by asking if any aftermarket devices have been installed. Aftermarket devices may be the cause of the electrical concern. Below are a few examples of unusual electrical concerns caused by aftermarket devices. Examples: 1. Devices connected to the DLC-2 (battery discharge/DTC stored) 2. Devices plugged into the 12V outlet 3. GPS tracking device (engine no start/battery discharge) 4. Dash cam (DTC stored)
full bulletin at NHTSA ↗2016 Mazda CX-9 engine problems
moderate Owners of the 2016 Mazda CX-9 have filed 49 NHTSA complaints about the engine at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Complaints
49
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2012 CX-9 | 14 |
| 2013 CX-9 | 13 |
| 2014 CX-9 | 13 |
| 2015 CX-9 | 12 |
| 2016 CX-9 (this page) | 49 |
| 2017 CX-9 | 34 |
| 2018 CX-9 | 62 |
| 2019 CX-9 | 15 |
| 2020 CX-9 | 3 |
When does it fail?
Of the 49 engine complaints filed for the 2016 Mazda CX-9, here's the actual mileage breakdown — failures cluster heaviest at 100,000-125,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Engine accounts for 49% of every owner complaint on file for this vehicle — the dominant problem area across 5 categories tracked.
Owners have filed 49 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This Service Alert supersedes the previously issued SA listed below: The changes are noted in Red. SA-011/24 02/12/24, 06/06/24, 07/29/24 DESCRIPTION Mazda has developed factory recommended scheduled maintenance services that support all major vehicle systems. Mazda recommends dealers follow the scheduled maintenance tables as cited in the vehicle-specific workshop manual or owner's manual. Services performed outside of Mazda's factory scheduled maintenance are not recommended. These services are unnecessary and create unneeded expenses for your customers. SCHEDULED MAINTENANCE Refer to the applicable Workshop Manual or Owner's Manual for vehicle -specific manufacturer scheduled maintenance.
full bulletin at NHTSA ↗This Service Alert supersedes the previously issued M-Tip(s) listed below. The changes are noted in Red text. MT-002/19 09/30/19 and 12/19/19 DESCRIPTION If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly, the replacement engine may fail prematurely. Metallic debris from the old engine (with catastrophic internal mechanical failure) may rest inside the intake manifold. When the new engine assembly is installed, debris in the intake manifold will be ingested into the new engine and cause internal damage. Clean the intake manifold
full bulletin at NHTSA ↗Some customer's might state that they notice fluid or oil leaking/dripping on the ground when the vehicle is parked. For this concern, inspect the vehicle for any trace of a fluid or oil leak and use the following examples as a guide to determine if it is severe enough to require a repair, or just to clean the area and monitor it at the next service. Examples of residue or seepage that may not be considered a leak and that may not require repair based on splash shield inspection.
full bulletin at NHTSA ↗Mazda Motor Corporation has decided to conduct a Customer Service Program (CSP11) to extend the limited powertrain warranty to 10 years or 120,000 miles, whichever occurs first, for necessary repairs if the covered vehicle has coolant leaks at the cylinder head, around the exhaust manifold. A dealer must inspect and confirm the covered vehicle is exhibiting coolant leaks at the cylinder head around the exhaust manifold matching Technical Service Bulletin 01-002/23 (Feb. 10, 2023) for the repair to be covered.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2016 Mazda CX-9s with the 2.5L turbo engine describe a recurring cracked cylinder head that leaks coolant. The failure is a known manufacturing defect—Mazda has issued multiple technical service bulletins (01-002/23, 01-013/21, 01-007/22, 01-003/21) acknowledging that residual casting stress and external forces from the exhaust system cause the heads to fail. Yet no recall has been issued.
The leak often appears quietly: a sweet smell in the cabin or engine bay, green coolant spots on the driveway, sometimes nothing until the owner notices overheating. Mileage at failure ranges from 50,000 to 134,000 miles, clustering around 70,000–90,000. Many owners report zero warning lights before the problem surfaces; by the time the temp gauge climbs or the check engine light triggers, coolant has already escaped.
Repair requires either head replacement ($3,400–$6,000) or full engine replacement ($7,500–$14,000)—many shops quote both options at similar prices. Dealerships routinely deny warranty coverage, citing mileage thresholds or—astonishingly—blaming owners for "operating while overheated" despite no warning signs.
One owner's replacement engine failed identically two years later; another lost power and automatic braking engaged after engine replacement. Several owners describe stranding on highways with families aboard or barely making it to the shoulder before stalling. Mazda corporate refuses goodwill coverage, leaving owners with four-figure out-of-pocket bills for a defect they did not cause.
Same Mazda CX-9 engine reports on nearby years: 2014 · 2015 · 2017 · 2018 · 2019
Failure modes owners describe
Cracked cylinder head with coolant leak
Cylinder head develops cracks that allow coolant to leak, typically from the exhaust side or rear of the engine. Cracks originate from residual manufacturing stress in the casting; external forces from exhaust system vibration (especially over bumps) can trigger failure. This is a known defect with multiple TSBs issued (01-002/23, 01-013/21, 01-007/22, 01-003/21). Owners report finding coolant puddles on garage floors, often without prior warning lights.
When: Typically 50,000–134,000 miles; many failures occur around 70,000–90,000 miles. Some failures reported as early as 2,000 miles on replacement engines and immediately after water pump replacement.
Symptoms owners cite: Sweet smell of coolant in cabin and engine bay; Coolant leaking from engine, visible on driveway or garage floor; Engine overheating warnings on dashboard (when they appear); High engine temperature gauge reading; AC becoming warm, fan running abnormally loud; Loss of coolant requiring frequent top-ups (one owner adding a gallon every 3 weeks); Engine stalling or loss of power while driving; Check engine light (sometimes absent until failure is advanced)
Codes mentioned: P0128 (coolant temp malfunction), Cracked head gasket codes (specific codes not cited in narratives)
Repairs/costs cited: Repair requires replacement of cylinder head ($3,380–$5,965) or full engine replacement ($7,479–$14,000). Some dealers quote replacement heads at prices approaching full-engine cost. Parts: new head, gasket, sometimes radiator and hoses ($2,691 additional). Labor and parts bundled with extended work time (5 months in one case; multiple shop visits common). Aftermarket shops and independent mechanics perform the work; dealerships often frame it as engine replacement to avoid customer shock.
Recalls/TSBs owners mention: Mazda issued TSB 01-002/23 (02/10/23) and earlier bulletins (01-013/21, 01-007/22, 01-003/21) acknowledging the defect and root cause (residual stress + external forces). No recall issued. Mazda Extended Confidence warranty (MEC) and standard powertrain warranty deny claims citing mileage thresholds or owner fault. Corporate refusals documented in multiple complaints; one owner received $1,000 dealer discount only. Mazda referred some owners to file NHTSA complaints rather than provide goodwill coverage.
Crankshaft sensor damage during engine replacement
When a new engine is installed, the crankshaft sensor is damaged during the replacement process, causing the vehicle to not start and requiring a second repair visit.
When: Immediately after new engine installation (same day or within hours of receiving vehicle from dealer)
Symptoms owners cite: Vehicle will not start after engine replacement; No start condition requiring tow-back to dealership
Repairs/costs cited: Replacement crankshaft sensor; no cost cited (warranty labor assumed on engine work).
Engine stalling and unintended automatic braking after engine replacement
After engine replacement, the vehicle dies at speed and automatic emergency braking engages without driver input. Cause traced to an engine sensor (specific sensor not named in narrative) that was either damaged during installation or malfunctioning in the replacement engine.
When: Shortly after return from first engine replacement; recurred on return trip from dealer after initial repair
Symptoms owners cite: Check engine light illuminating; Engine stalling while driving at speed (40 mph in reported incident); Automatic emergency braking engaging unexpectedly; Engine dying without warning
Repairs/costs cited: Dealer eventually identified and replaced a damaged engine sensor; required extended test driving by dealership to verify fix. Work completed over extended time (returned 07/07 after initial visit 05/20).
Replacement engine overheating shortly after installation
A vehicle that received a full engine replacement due to original cracked head later experiences overheating with the replacement engine. Suggests possible installation defect, incompatibility, or a second defective unit.
When: Approximately 2 years after first engine replacement; second engine failure at 86,000 miles total
Symptoms owners cite: Engine overheating; Coolant loss
Repairs/costs cited: Requires second full engine replacement; cost not specified. Service advisor noted issue during routine service 5 months prior but did not recommend action.
Coolant leak into engine block and cylinder walls
Coolant breaches the cylinder head gasket and enters the combustion chamber or oil galleries, mixing with engine oil. This causes internal engine damage and eventual seizing if the leak is not caught quickly.
When: Variable; one owner reported coolant mixing with oil requiring full engine replacement at 67,000 miles
Symptoms owners cite: Coolant leaking from engine; Engine block cracking or warping; Oil and coolant mixture in engine galleries; Engine seizing (risk, not always realized)
Repairs/costs cited: Full engine replacement required (cost $7,000–$14,000).
Synthesized from 49 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 14 most recent
Dealer diagnosed manufacturing defect that caused crack in head. {Which could lead to engine failure, and subsequent accident due to engine failure during operation.} Engine lost coolant. No overheating noted. No warning/error codes noted.
My engine head cracked whiling driving. sudden lost of complete power in houston texas at a 75mph speed. Was able to safely pull to the side. took it to the dealer where they confirmed it was a cracked engine head. Its a common issue with this model from 2016-2019 no warning light came on just lost 90% power. was able to restart and drive the 7 mins to the dealer.
Car overheated. check front engine and could not see any visible leaks. check all around the engine and found coolant leaking from the back of the engine. confirm by dealer that is leaking at the cylinder head.
Engine failure with crack in the engine after a loss of coolant fluid.
I am being told by the dealership service center that there is a coolant leak from the engine. A previous coolant look due to a hose was repaired but this is a separate issue related to the TSB for coolant leak at the cylinder head Bulletin 01-007/22
Engine is leaking coolant. Took the car to Horne Mazda of Avondale dealership for inspection, was told coolant is leaking from cylinder head. Was told the engine overheated and both cylinder head and cylinder block warped and will need to replace the engine. I feel my safety and others were at risk because the car could have lost power and stalled in the middle of roadway at any time due to…
While driving, engine suddenly overheated due to coolant leak from cracked cylinder head. This was a known issue per the TSB 01-002/23. See attached. Vehicle only has 55k miles and has been maintained, only requiring oil change, topping off of fluids, and filter changes. Dealership has determined that it will require a completely new long block. Mazda USA is currently only willing to cover a…
Head gasket leaking and caused major engine issue at 89,000 miles. Mazda has known of this issue, but refuses to recall it.
Cracked Cylinder Head due to Coolant Leak - SB 01-013/21. This is a known issue with Mazda, yet it has happened with the vehicle being serviced regularly. This is happens directly after the warranty period and it is not being covered.
While my wife was driving her 2016 Mazda Cx-9 Grand Touring on the freeway, many of the dashboard indicator lights came on warning her the engine was over heating and to pull over immediately. While she was attempting to move over to the shoulder, smoke appeared from underneath the engine hood which made it difficult to safely move over to the shoulder. She believed the car was on fire so…
Had engine trouble with your 2016 Mazda CX-9?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2016 Mazda CX-9?
It's a documented issue but not catastrophic. 49 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Based on the 49 complaints filed, engine issues most often appear around 115,333 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2016/Mazda/CX-9.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.