[andrew20195]

Originally Posted by BoostedInPhx

Part of the problem with the short trips occurs because the oil does not get hot enough to evaporate out the water and unburned fuel in it. The oil normally gets contaminated with water and fuel that get past the piston rings during normal operation. The water and fuel are not good lubricants.

Exactly. Not only are water and fuel not good lubricants, when they mix with motor oil, acid is formed. This leads to etching of the bearings, thus, excessive wear. That's why short trips cause more engine wear than trips where the engine is allowed to reach full operating temp.

Of course, all of this is taken into account by the computer's oil life calculations, so as long as you change your oil when you're supposed to, it won't make a huge difference in the long run.

[FirstClass]

Originally Posted by SpdFreak

I'm not sure, but they might be referring to those that don't warm up their cars in the morning after it was sitting in the driveway for the past twelve hours in 18* (degree) weather. Please correct me if i'm wrong.

No. Warming up your car in the driveway is bad for the engine, not good for it. You should always start driving as soon as you start the car.