With your mileage I would be using a minimum 50 weight oil, but even better with a decent 60 weight like millers.
As the car is new to you I would do a mega service first replacing fuel filter, oil/and filter plugs, and all sensors but at least the all important CTS, coolant temp sensor, at the rear of the head under inlet manifold by dipstick tube, this is most important.
Make sure also the belt and tensioner are done unless you know they have been in the last 25,000 miles, 3 years, just not worth the risk otherwise.
If not already done so rewire the fan circuit, before it burns out, and also rewire the fuel pump circuit.
tabetha