Metal in my Oil LR2 2013

[Tommilousis]

So, after some time has passed the car has been working really well. That minor rattle at the beginning for one or two seconds remains when the car is cold but goes away after. The car was smelling like oil but then I did an engine shampoo and that took care of that. However, when I have driven for approximately 30 minutes or more and I am idling sometimes the smell of oil comes in the car. All in all I think it is working well and I don't believe a lot of engine damage was caused by the failure of the sprocket. My last question would be to try to find the root of how the failure to the sprocket occurred. I recently changed my coolant with 'Prestone all vehicle' - could this be the case? Could it have gotten to hot and caused an issue like that should I be using another coolant. I got a Jaguar specific European coolant for Land Rovers but I was told that it doesn't matter, the one I purchase is just fine. Last, is Blackstone a service in Canada?

 

[Rover Range]

The sprockets fail due to poor machining of the housing. There's a weak spot at one of the fasteners.
Oil changes and coolant quality has no affect on their life span. Does not seem to be failing on, but a few vehicles.

 

[Tommilousis]

Again, more time has passed and the car is ok. Do I need to replace the sprocket? And should it get the fasteners checked and fixed? Last, the car always smell like oil and gas now after it gets going and heated. Is this a result of the damage, missing sprocket or other? I've had it engine shampood. Could there still be risidual oil everywhere causing this?
Apologies for all of the questions. I've appreciated your expert help.