Brought car in because heater was not working. They performed coolant flush. was still in parking lot and heat still not working. They took it back in. Heat worked intermittently over next few days. Before we could bring back, warning for engine coolant light flashed a few times, then went out. Drove it under 25 mph directly to service.

Told there was a leak at the cylinder and would have to replace the engine.

Car is brought to dealer service for regular maintenance religiously. Should this have been picked up earlier before the (severe) damage was done?

Our 2016 CX-9 with less than 78000 miles started smelling strongly of coolant inside the car. There were no visible leaks and no issues with temperature so we took the car in. It was leaking coolant from the cylinder head. This is a KNOWN problem with this engine and there is a Mazda TSB addressing it.

Our 3rd party aftermarket warranty would not cover this repair because it was considered a "manufacturer defect"! Our local Mazda dealer (where we took the car for repair) estimated the work (replacement of the head) at ~$7,000. The dealer approached Mazda corporate about the issue, since the vehicle was out of warranty, and they were willing to "comp" the repair at $2800, but because of other things that needed to be done (like the replacement of belts) it would be closer to $3000 in the end.

Our car went into the shop 11/8/2022 and we have yet to get it back on 01/08/2023!! We are supposed to get it back next week. The transmission had to be replace also. That is under another complaint. The fact that Mazda would not stand behind their product (even though it was out of warranty) and fix this vehicle for free (as they should have) means that our next car will NOT be a Mazda.

I drove my 2016 CX-9 off the highway and it idled at front of a restaurant for about 5 minutes, when suddenly the engine coolant overheat light came on. I shut the engine off and found leaking coolant on the ground near the rear of engine bay. Brought the car to Corpus Christi Mazda, where I found out leaks come from cylinder head crack. This happens to CX-9s manufactured before June 20, 2020 according to Mazda TSB 01-013/21. I was quoted $3380 to replace the cylinder head out of pocket because the car is just out of powertrain warranty. I contacted Mazda headquarter for covering the cost out of goodwill through AWA (after warranty assistance) program since this is due to manufacture defects of cylinder head. Mazda refused to pay.