start and go?

I've owned many SOHC and DOHC vehicles in my life and most, if not all made some pretty ugly noises when driven above 2000 RPMs when they're cold. Personally, I think valvetrain components are a little out-of-spec when they're really cold - valve lash is a bit off until everything reaches operating temps. Combine that with the fact that oil does not circulate nor lubricate as intended until it's warmed.

I lived in Wyoming for 17 years, and 9-months out of the year it's a necessity to warm cars up before leaving home....or it's a miserable drive until things warm up. With the noises I hear from my Frontier, I can't imagine anything good is happening to the engine under those conditions, so it warms up for 5-10 minutes, depending on the temperature before I pull away. The engine sounds happy, I'm happy because I'm not holding a icy steering wheel and sitting on a frozen seat. I've had no ill effects from any of my 16 cars from giving them a morning warm-up.

A few guys on BITOG claim 'fuel dilution' from morning idling, but if that condition truly exists, wouldn't a lot more of us that sit idling in traffic jams every day suffer more main and rod bearing failures than we do? If there is fuel dilution occurring, it's minimal and not a worry.

I think this topic will always up bring questions (especially during winter) because everyone has a different opinion/experiances. So I don't think that we will be able to get a definite answer.
But, since forums are places where peaple can state their opinions, here is mine.

Back in the day when most cars had carburators warm up time in winter was pretty much a must. Cars were very sluggish and stalled a lot when they were cold and that did not require temps well below freezing.
Now, with fuel injection that problem is completely gone. And with temps above freezing you can start and go right away rather safely (that is what most manufacturers recommend). When its really cold (like -20C in Toronto for a couple of weeks) I like to leave the car running for 2-5min.
I did an experiment ones. The temperature was about -10C and I left my car running for 15mins. When I was going into the car I thoght "Great, my car is nice and warm inside by now", well the needle was bareley close to the quarter mark (when its fully warm it is almost at the half mark).

So I guess that manufacturers are partially right by saying that the car will warm up the fastest when driven.

I still let my car idle for about 2 mins, 5mins is preatty much max as my experiment had shown that it just wastes gas and doesnt warm the car up.

I guess that either prolonged idleing nor driving right away will kill your car, so use your best judgement.