I haven't been able to find anything on this topic and maybe it's because the wear is insignificant but I would still like to know, no matter how insignificant the wear, which scenario wears the engine less. This is on a diesel engine.. On a 0F day, 3 identical diesels start up at the same time and after 30 seconds to get oil pressure and everything moving, diesel 1 takes off, slowly getting up to speed. Diesel 2 turns on the exhaust brake to put a load on the engine and sits there. Diesel 3 just idles. As each diesel hits 100F coolant, how would they rank in wear over the period from the end of that initial 30 second wait until each hits 100F? As in, which one would wear the engine the least and which would wear the engine the most, and more importantly, why!? I have read about people saying idling causes twice the wear as driving it and vice versa and I'd like to see what you guys say about the issue. I can see idling it for a long time being harder on it since the engine doesn't warm up as fast, so it would have a cold engine block being a huge mass of steel, yet the aluminum pistons would easily capture heat and expand but without the block being able to expand until later as it slowly heats up. Starting and driving or idling with e brake puts a load on it which would expand the piston even more (since its even hotter) but the engine heats up quicker. So I still can't determine which is better. As always, thanks for any and all help!