Most of my trips would be in the region of 15 or 20 minutes, and I like seeing the coolant temp come up fairly quickly. But I wonder does that mean the oil is then hot enough to drive off any water or other contaminants, and the exhaust hot enough to burn off any corrosive nastiness? I imagine it would take a bit longer for the whole system to get cooking. Probably a good excuse for an Italian tune -up every so often. Thoughts?