re: the idling diesel pickups- yeah I leave mine idling while fueling up, just a few minutes..if the pump is as fast as it should be less than 3 I'd say.
As for wearing out the starter- yeah I've bought 2 starters in 185,000 miles, and they aren't inexpensive, I figure one of them cost 10x more than all the fuel I've ever used idling for a quick stop.
Now I do have a system I designed and built to leave my truck idling on either a timer or as long as I have a hidden switch flipped.
The engine must be on and running with the key, then I flip the hidden switch and remove the key, lock the doors and I'm away.
Truck stays runnng but can't be driven, shifter is locked and if someone was to break in and try to steal it while idling as soon as they touch the brake pedal to try to move the shifter it shuts down. If they happen to find the hidden switch they still can't restart it without the key.
Why do I have this? --The timer function is for turbo cool-down - I like to see my EGT drop below 400 after a hard run before shutdown, so shoot me. Sometimes I want to jump right out of the truck when EGT is still high after a hard pull without sitting there waiting. Usually a minute or so will do it.
The other, and main, reason is because it gets HOT here in the south and occasionally while travelling with our two dogs I'll leave the truck running with the AC on for them while we grab a quick meal.
I wonder what the anti-idling laws would say about that? Can't leave the dogs in a hot truck, its cruel and illegal in itself...can't take them into the restaurant, can't leave the truck idling...hmmmm
Oh BTW what fuel additive should I use when the tractor is idling while I weld on my bucket hooks? And does it really matter if I use SUDT while operating the bucket with the hooks on it or should I use Amsoil?