2016 Mazda CX-5 GT AWD w/Tech Pkg
- Plano, Texas, USA
In general I agree that the culprit could be a batch of bad cylinder heads be produced. But the cylinder head used on 2.5L with cylinder deactivation is different from the one for non-CD 2.5L, and it could make some ill-effects when Mazda re-designed or modified the previous cylinder head for additional and different components used by CD. I’d say the problem can be CD related. We’ll find out when NHTSA posts the related documents for more details.Although I have a very negative opinion of cylinder deactivation, based on multiple other issues, I've seen nothing which connects CD to an oil leak. Information from other threads and sources indicates that there were a batch of heads produced which have manufacturing defects, and are the root cause of some external oil leaks.
If you ask the service advisor who mentioned the cylinder #3 leak, perhaps he/she would confirm a defective cylinder head on your vehicle.