2016 CX-9 with 91,000 miles.
I noticed the coolant level in the tank was consistently low, even after adding more. After a week of repeatedly topping off the coolant every other day, I removed the engine undercover and discovered a messy green residue all over the place. I contacted MazdaUSA and confirmed that my 2016 CX-9 is still covered under the CPO Limited Powertrain Warranty until 7/28/23 or 100,000 miles, which is just about another two months in my case. Initially, I suspected a leaking water pump or gasket when I brought it to my local dealer. However, they informed me that it was actually a crack in the cylinder head. Fortunately, this issue will be covered by my CPO warranty, but I'll have to wait for a week to get the replacement part. In the meantime, I'm using the dealer's courtesy vehicle for free since Mazda does not cover the loaner car. I'm uncertain about how long I should remain optimistic. I had plans to continue driving my CX-9 for a long time, but now I'm not sure what to expect.