Ever wonder how long you should idle your diesel engine for it to warm up? It's about 5 minutes. Apparently many folks are under the illusion that they need to idle for an hour or so... the earlier in the morning it is, the longer they seem to idle. I hate those people. For us, by the time the air buzzer goes off and our air brakes can be released, the engine is warm enough. We aren't going anywhere until the brakes can be released anyway.
pg 2 has some interesting Myths debunked.
This is a RV page but they called the Cummin's Customer support to get their answers...
Check out the home page for various articles. They have some good ones.