When I have to make short trips in any of our cars, I turn the heat off and use only the seat heaters. Less heat removed from the cooling system= quicker coolant warm-up= quicker warm-up of the oil at the oil cooler (paradoxically) since the water temp is always up to operating spec faster than the oil.

X5's have oil coolers right? I've always done this in my Prelude and never thought about finding out if the X5 even has an oil cooler until it just struck me now.