2017 CX-9 Possible Cracked Cylinder Head - Just Past Powertrain Warranty

Hi.

Currently at 76k.
Bought this from Audi of Mississauga in August 2021.
Powertrain Warranty expired Dec. 7/22.

Anyway, I had heat problems starting a couple of weeks ago. Even after remote starting, dash, floor and defrost vents would blow cool air but rear cabin was blowing hot as usual. Would drive for 10 minutes before the heat would kick in up front. The front blows air in all settings it's just that it would blow cool for quite a while.

Spent hours trying to diagnose. There are three blend door acutaors up front. Beside gas pedal and two beside glove box. Only the top one beside the glove has a lever to turn and that turns fine. Only one door is visible and that's the one for the circulation setting. With the glove box out you can see that opens and shuts. I think the actuators are fine. It would be odd if more than one failed up front at the same time. Whether it's on auto or dual setting, it's the same heat problem.

There was a TSB for poor heater performance and I followed that regarding checking the inlet and outlet hoses from the HVAC box. Checked out fine using my thermometer. After running car for a while without heat ON, the inlet and outlet hoses were fairly close in temp around 40. That's the prodecure and it was fine. So doesn't appear to be plugged heater core.

Coolant has been leaking out. I didn't notice right away because a few weeks ago I had both cars rust proofed and that dropped tonnes of grease on my driveway. When I finally noticed, I check the reservoir and it was 1 inch above L. So got the coolant from Mazda dealer and topped up. Drove car a few more times and it dropped 2 inches below F. No warning light and no white smoke from exhaust. Oil on dipstick looks fine to the naked eye and not milky. No overheating. Needle is right in the middle.

It's not right under the rad as I can see no fresh fluid on the tray there. It's I figure a good 12 inches further up toward the cabin. I put a pizza box down to see the drips. I can't say for sure if it's say leaking at the thermostat for instance or somewhere else. I see no wet spots anywhere inside the engine bay but it's pretty compact in there.

The worst case scenario is a cracked cylinder head and coolant was mixing with my oil during the times I was driving. I eventually stumbled upon this after much research. Lots of people on Mazda forums posting about this. Lots of them had it happen past warranty and it's a known problem. They said Mazda goodwilled engine replacement or at least the cylinder head, though I don't know how many were Canadian. And there's lots of talk of possible class action but nothing concrete so far. I examined for cracks around where the exhaust manifold meets the engine and I can't see anything. But impossible to see the back of it. Here's the TSB: https://static.nhtsa.gov/odi/tsbs/2022/ ... 0-0001.pdf

I am waiting for Audi dealer to call me back but I talked to the local Mazda where I got one oil change done and tires. But I didn't get my last oil change done there because the timing didn't work out and I had to go a couple hours up north. So did it at a Goodyear franchise close by. I keep all invoices. Dealer Service Manager said he doesn't think Mazda will cover this even if it's just one day past powertrain warranty. And they've only seen my car twice. He said you should try calling Mazda customer service.

I haven't driven this for four days now. I don't mind the $149 diagnostic at the dealer but I kind of what some input before I get CAA to drop it off there and do that.

Wondering if any of you can provide some advice based on past experiences. An engine replacement would be pretty catastrophic to my finances.

If I call Mazda customer service, any suggestions on what to say? Never had to do this before.

Thanks for the input.