I got an update. 2015 Mazda BT-50 3.2L 5 cylinder turbo diesel manual 127;000kms or (78;914) miles, I forgot to give you the milage last time sorry. 

I took it into the Mazda dealer for the service and inspection of the puff of black smoke that exhales from the exhaust every gear change, they completed the service and gave it back to me and said there's nothing wrong with it, they said it's normal for these models to puff smoke like that, but said they did a injecter relearn. But loan behold I see the puff of smoke just about each gear change behind me in the night in cars headlights behind me, who knows maybe it is normal. I wasn't too happy with the service either, typical sloppy work performed you might get from the dealers, forgetting to put the rubber shield back on that covers oil filter back in place and sloppy job of cleaning the car, and not listening to instructions that I gave them when I went in and booked the service. I had to double tell them not to this not to that etc, not taking it back to them, I'm just gonna do the sevicing myself again. And next time take it to the machanics that I know and have worked with around the corner.

I know you said you haven't worked on these models before, but from the top of your mind what can cause an occasional clattering/ticking noise from the engine opon start ups warm and cold, with these Volvo designed 5 cylinder engines that where built by Ford in Thailand. They have timing chains, could it be a possible timing chain issue or could it be valve clatter? It stops after 2 minutes with the engine running.

Any ideas? Cheers and keep giving good info about cars everyday.