My experience with my car, and as always YMMV, is that the coolant will come up to temperature very quickly, but the oil takes forever to warm up. I have to be driving on the highway for almost 40 minutes, about half of that at 100km /hr on the highway before the oil is most of the way up to temperature (170 F). Even then, the oil is still about 20 degrees below the temperature it'll level out at (195 F). Just the viscosity difference would be significant (but small). I also find with my car that the car runs a hair rich till it's most of the way up to temperature.
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