Drain the engine oil and coolant. Remove the left (front) exhaust manifold. Remove the hose retaining bracket nut and bracket, then disconnect the hoses from the oil cooler. On 2GR-FE engines, remove the center union bolt and take out the oil cooler and O-ring from the engine block. For 2GR-FKS engines, remove the two nuts and two bolts, then separate the oil cooler from the side engine block and discard the oil cooler gaskets. Ensure to install a new O-ring and plate washer or new gaskets based on your model. Tighten the nuts and bolts to the specified torque. Installation follows the reverse order of removal. Finally, add oil and coolant.