Global warming I purchased a vehicle with an om606 and it starts fine at -1f, it rattles pretty good and not much heat for about the first mile though. Started it at work one evening fifteen minutes early at +7f and idled for 15 minutes and not much cabin heat and temp gauge was still at 40. I guess they use such little fuel at idle it does not produce much heat, so no benefit from warming it up much unless the inside windows are frosted up.