If a torque wrench is required, you will need to use a wrench that is set to the correct torque specification. The torque specification for an oil cooler nut can vary depending on the make and model of vehicle. You can find the correct torque specification for your vehicle in your vehicle's owner's manual.
To tighten an oil cooler nut with a torque wrench, first make sure that the wrench is set to the correct torque specification. Then, place the wrench on the oil cooler nut and turn it clockwise until it is snug. Do not over-tighten the oil cooler nut, as this can damage the nut or the oil cooler.