A worn out pump won't put out too much pressure, it will only put out too little, so changing the pump is contra-indicated. Most 235's can't put out enough pressure to allow the pressure relief valve to open after they have reached operating temperature unless there is a blockage somewhere after the pump. Two miles is not far enough to get the oil up to operating temperature; it should take at least ten. Also the ambient temperature will have a lot to do with oil temp. I think it's colder now where you live than it has been recently.