First time poster, long time lurker. Need to vent. I own a 2018 Mazda6 Signature with the 2.5T engine. Car has 35,100 miles. Driving home from Vegas and start smelling coolant. Get home, look under the hood and discover coolant everywhere. I am familiar with the TSB about the head cracking. I checked my VIN and compared it to the TSB and, sure enough, my car is included in that issue. I drop it off at my Mazda dealer this morning and they tell me my Radiator Cap Housing failed and was the cause of the coolant leakage. And, this is not covered any longer because my basic warranty expired (3mos, 36k). Is this total bull$hit or no? Should the cooling system not be considered part of the power train 60 month, 60k mile warranty???

I am so pissed at Mazda. I called two different Mazda dealers and they both confirmed part PYLM1517YB (the radiator cap housing) is not covered under power train. I am out $750. I've been a Mazda buyer for life. This will change that for me.

 

Cooling system except parts directly connected to the engine like water the water pump (and this may be subjective to be covered) generally are not in the powertrain system. Not just MAZDA but most vehicles.
Powertrain usually means the engine transmission and trans axles or differential. Example the ECU control or effects all those 3 mentioned and it is not covered under power train with most all manufactures.

As for not buying MAZDA in the future if you take your thought about how you think things should be you will soon run out of choices of vehicle manufactures to buy from very quickly.
Personally, I would keep all the records of this event should the engine have issues that can be related to that part failing causing extreme coolant temperatures.