Very little to do with the CX-5 (albeit somewhat obliquely) but I was skimming through the latest issue of the Caravan Club Magazine - yes I'm one of those - and came across a test of the SEAT Leon TDI. What caught my eye was that the tester referred to the Start/Stop feature (similar to iStop I assume) in disparaging terms.
".......... I may have switched off Start/Stop in the interests of reducing engine and turbo wear. But if it wanted to risk its turbocharger frying at every switch off, that's its own choice - though replacement turbos are not particularly economical......."
Now assuming the SEAT has similar engine management systems to the Mazda, surely this feature isn't going to activate if the turbo is still spinning or dangerously hot? Have I misunderstood this or is the guy a dinosaur?
From memory the CX5 handbook states that stop/start feature will not operate if engine temp is high. When I was towing my caravan up a long highland gradient last summer I pulled into a layby on the summit to see if I-stop would work but to my relief the engine kept running so turbo would be lubricated and cooled.