srv1, it would appear you know the textbook definition of severe service. Now the question is, can you tell my why the textbook says what it does? You obviously don't know.
A cold weather climate is considered severe because of heat up and cool down cycles. Not because it's cold outside. When the car is cold, the engine gets a very rich mixture, which has a tendency not to burn completely, and mix with the oil. That washes out some of the oils ability to lubricate. Furthermore, upon cold starts after sitting long, oil pressure drops to zero, the oil becomes thick and slow. When the car is then started, you have no oil pressure, which wears on the contact surfaces of the engine.
Now, LS1 powered police cars (all Fbodies and Corvette's if there are any of those in duty) are not generally subject to most of that contamination, or wear. They don't get started from cold frequently, and they aren't running cold very long.
So the police are on the brakes hard a lot. For a highway patrol car they stop hard, and make quick turnarounds. Last I checked, stopping hard has very little to do with engine wear. Accelerating hard does, but would be limited by safe pursuit speeds. Most of the time the highway patrol Camaro's and Firebird's are not in a severe duty cycle on the engine.
5000 miles is the recommended interval, then, fine. There is something else you might want to look at. Why it's rated at 3000 or 5000 or whatever. Contamination is the chief reason oil is changed. Contamination from burning fuel, unburned fuel, from the intake charge, etc. Most of which comes from cold running, and some from internal wear. If those are minimized, so is the contamination of the oil.
Oh yes, and quit whining about idling, it hasn't been nearly the big deal it used to be. Cars run WAY cleaner at idle than their predecessor's and oils and oiling systems are better as well.
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