I start my car and let it warm up because I dont like sitting on cold leather seats. I would rather go out to a nice warm car.

The other day I started it up, locked the door, went back in the house, got side tracked and forgot the car was waiting for me. Took at least an hour and a half for me to remember I started the car already.

I think I have lost a glow plug or two and my car is a little hard to start on cold days unless plugged in. A couple of days this winter the temp outside was zero.... Every time I went somewhere my car was stone cold and hard to start. So I just left it running. I think it ran about 8 hours one day.

I was on the highway 2 weeks ago at 5am and was getting way too tired to keep driving. I pulled in a truck stop and fell asleep for over an hour... I left it running then too.

I was always told it was ok to let a diesel run. Doesn't concern me one bit. In the military we let diesels run forever. My junk yard, my brothers friend owns, leaves their loaders run for days at a time.

just my .02