I've heard both Art Stanley and Tony Athens throw around gallons burned too, and both said 30,000-ish before rebuild for the 300+ hp B series. Art of course said Deeres last way longer.It's more about fuel use then hours. But they are related. You can expect a rebuild between 30000 and 40000 gallons of fuel use. So if you burn 1gph for 20000 hours you're still in the workable life. If you burn 12gph for 3000 hours,. Then a rebuild is on the horizon. On average a 330 or 370 is good for 5000 hours of mixed use with good maintenance.
The idling thing is funny. I think it comes from truck stops who run all night in cold weather to keep the cab warm...but guys seem to think no-load idling diesels is the thing to do. My understanding from Tony A is no-load idling should be minimized, warm em up in gear at low rpm.Well yes and no. I have seen a lot of harm done just sitting idling using the engine as a battery charger (sail boaters). No real amount of fuel burned but lots of carbon build up and glazing of the cylinders. I have know owners scared to hit full throttle because fear of taking life out of the engine when in my opinion a diesel engine should hit full throttle a few times per season.