Pilonrock..
Actually it's the other way around. Most pilots couldn't be bothered looking in the cowls when I was there. I also never once saw a pilot on the cabin roof of even a 412 where there's lots of access and space to stand.
How many Bristow pilots did a walk around after the flight? None, never saw one.
It's assumed to be an engineering task
That's been my general experience too, the larger the helicopter the less pilots look it over.