Make sure that your fan is working well with a new thermoswitch. This switch senses when the oil temperature gets hotter than a certain amount, and then turns on the fan. The stock switch turns on around 240-degrees Fahrenheit (110-degrees Celsius), but you can replace it with a cooler one that turns on at a lower temperature. Some slight wiring modifications may be required in order to use the cooler thermoswitches (they have different connectors on their ends).
Thermoswitch for Fan - Late-Style Carrera Factory Oil Cooler, 110-degrees Celsius (requires 1 900-123-007-30-M131 Sealing Ring) Brand: Genuine Porsche [More Info]
Sealing Ring for Thermoswitch for Fan - Late-Style Carrera Factory Oil Cooler Brand: Fischer & Plath [More Info]
Oil Cooler Air Scoop
Does your Porsche operate at a higher oil temp than you would like? Placing the front-mounted oil cooler in the right wheel well was not the best design decision for the 911. Trapped in this wheel well, the oil cooler actually radiates a lot of its heat from the lines that run up the side of the car. Now, with the addition of our Oil Cooler Air Scoop, you can supply your starved front-mounted oil cooler desperately needed fresh air. The Scoop directs cooling air right onto the oil cooler area in front of the right front tire. Manufactured out of fiberglass, the grain and texture of this scoop is designed to match the look of the rubber bumper pieces. Blends in so well, you would hardly know that its there, except for the cooler temperatures! The installation procedure and results of cooling tests can be found in our Pelican Technical Article: 911 Oil Cooler Scoop Installation.