I am on my third CX-9 as a lifelong Mazda owner and my 2017 Signature model has a coolant leak at the Cylinder head which is caused by a design defect. Mazda extended their warranty to 120K miles and they are aware of the issue. I'm at 140K miles and they won't cover the repair. Service bulletins say to replace cylinder head but service department is saying new engine $8700. What can I do? Why is there even a warranty mileage limit on a design defect?????

 

Welcome to the forum

 

Sorry to read this but as you said Mazda extended the WARRANTY and you even went passed that?
Unless you had this as known record on your VIN then you don't qualify for the warranty or warranty extension?
Sorry to say but the only thing you can do is ask the dealership to start a case directly with MAZDA corp. But unless you can show valid prof from a dealership or licensed service shop prior the 140k miles be prepared to get turned down for a warranty coverage.

Example my friend owns a completely untouched right down to a flid with caps 12 volt battery and old style hose clamps 1973 Ford Pinto with less then 10,000 miles. It was stored for decade by family and well preserved in the factory business warehouse. Should he get FORD to cover the retro fitting and parts needed during that worldwide recall of exploding Ford Pintos ? And YES it is the same example as your MAZDA and the head!

The bottom line is I am not sure why a new member only joins to post negative information and not even ask what can I do! You may get some feeling sorry for you but not one MAZDA forum and any member has the power to change Mazda crop mind in there discission..
And class action suits generally fail cost money and by the time there is any settlement most owners trade in or sell their vehicles. As for a privately suit if USA small claims are capped at 5000 if you win. And civil requires about the same just to start a suit.