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Hello Everyone, Here’s a quick tutorial (PDF file at the bottom of the page) on: Replacing the Coolant Temperature Sensor on a 2004 Cayenne S without Removing the Intake Manifold Applicable models: Cayenne S (2003-2008), Cayenne Turbo (2003-2008) Symptoms: faulty temperature gauge, engine cold at touch even after driving, really loud (like jet engine noise) radiator cooling fans blowing cold air thru the air ducts, code P3081. The truck has about 105k miles. The coolant pipes have been changed at 74k miles and the coolant reservoir at 95k miles. On both occasions the system has been bled, vacuum tested and refilled with new coolant/distilled water mix, under pressure, using Uview AirLift tool, thus eliminating the risk of air being trapped in the circuit. The process is pretty straightforward, but I wanted to share a few tips on how to get around the problems that might arise. Although removing the intake manifold would make the job easier, I chose this pathway due to time limitations and mostly because of the weather. Plus removing the manifold has its own downsides: it would take way longer, plastic lines that crack, fasteners hard to access or stuck, gaskets on the manifold and throttle body that would need replacement, etc. Hope this helps. Parts needed: 1) Coolant Temperature Sensor 996-606-410-00 Tools needed: For Secondary air pump removal/install: 1) 3/8 T40 torx socket 2) 3/8 1-1/2" extension (optional) 3) 3/8 ratchet 4) 3/8 torque wrench 5-80 ftlb. range For Coolant temperature sensor removal/install 1) 1/2 22mm (6pt) deep socket 2) 1/2 3" extension bar 3) 1/2 universal joint 4) 1/2 10" extension bar 5) 1/2 ratchet 6) 3/8 1/2"adapter 7) 3/8 torque wrench Wear gloves, coolant is toxic. The job must be done with the engine cold. Depressurize the system by opening the reservoir cap (only after the engine has cooled down). You can choose to drain the coolant reservoir before removing the sensor, as coolant will start gushing out of the sensor’s mounting hole. I chose not to. I dropped a clean rag in the valley, right next to the sensor, and I covered the hole with it while swapping the new part in, as quickly as I could. I lost maybe 1/2 quart of coolant. For that same reason, I chose not to bleed/pressurize/refill the system again, as the loss was pretty insignificant and the coolant is relatively new. I just topped the reservoir up with fresh coolant/distilled water mix, and monitored for any discrepancies, smells, leaks. After replacing the temp sensor, I cleared the P3081 code So far, I can report that the temp gauge came back to life, never passed the 180° mark, the radiator fans are silent again, heat works fine, the engine feels warm all around, and the P3081 hasn’t returned. 1. Here’s the new coolant temp sensor vs. old sensor 996-606-410-00 (washer is included) 2. Location. On the left side (passenger) of the engine, right behind the intake manifold (upper left corner, next to fastener no. 5, the last one on that bank). 3. Remove the plastic covers by turning the plastic retainers until they release. (Mine were off already so I have no pics, but that’s pretty straightforward). 4. Remove the Secondary Air Pump. First, unplug the vacuum hose (yellow arrow), then unscrew and remove the three T40 torx screws (red arrows), and finally, pull the electrical connector up and unplug it (green arrow). 5. Pull the plug off the temp sensor. This part here is a little challenging. I reached the sensor with my left hand, from the top, and gently squeezed the top end of the plastic tab, towards the wire harness, and pulled up at the same time. It came off rather easily, but finding the right position to get a proper hold of it was a bit of an issue. Be careful here, you absolutely do not want to damage that connector. All those wires are 10+ years old, exposed to heat and elements and stuff, so approach with caution. 0 Here is the sensor with the electrical connector removed. Notice the hose that goes on top of the sensor, it is gonna make it pretty difficult to align your socket and the first extension. I managed to bring down the 22mm socket with my left hand and then slowly adjust it on top of the sensor while pulling the hose towards the front of the engine The problem is that given the height of the sensor, a deep socket is absolutely necessary, but that leaves almost no room to align your sockets and extensions. Here’s the removed sensor. I flipped the picture upside down to show how the socket fits the sensor when in the engine. Notice that the socket grabs the sensor just a little below its top rim. That’s why the 1/2 22 mm deep socket is a must. I don’t think a 3/8 deep would work here. 6. To Remove Sensor: This is the order of tools going into the engine, one by one, on top of each other 1) 22mm 6pt deep socket 1/2 2) 1/2 3" extension bar 3) 1/2 universal joint 4) 1/2 10" extension bar 5) 1/2 ratchet 7. Once the sensor breaks loose, turn once or twice and stop. Remove your sockets and extensions one by one, get a clean rag next to the sensor and follow unscrewing it by hand. Also, make sure you have the new sensor at hand’s reach, ready to go in. You should practice reaching in and out a few times using your best route of access, so that when you do the swap, you do it as quickly as possible. As you keep unscrewing, coolant is gonna start leaking out (given the diameter of the sensor, I don’t think there would be a massive coolant loss, but anyway, the less the better, not just for the obvious reasons, but also because it would be impossible to clean it up). Remove the sensor completely out of its mounting hole and cover the hole with the rag. Quickly bring the new sensor in, remove the rag and screw it in by hand. Make sure the washer that attached to the new sensor stays in place. Tighten it by hand and then re-insert all the tools back in, one by one, as it follows: To Install new sensor: 1) 22mm 6pt deep socket 1/2 2) 1/2 3" extension bar 3) 1/2 universal joint 4) 1/2 10" extension bar 5) 3/8 1/2"adapter* 6) 3/8 torque wrench* *not used in removing of sensor Tightening torque for coolant sensor: 30Nm (22ftlb.) 8. Reinstall the Secondary Air Pump on Bank 1 (electric plug, vacuum hose, and the tree T40 torx screws). Tightening torque for the screws: 10Nm (7.5ftlb.) 9. Top reservoir with coolant, and screw the cap on until it clicks. 10. Reinstall plastic beauty covers. 11. Using a code reader, clear all the codes you may have had. 12. Start it up and observe for leaks, smells, while closely monitoring the temperature gauge. (*As I warmed up the engine, whatever coolant leaked down by the firewall released a small puff of steam that went away within seconds). Good luck! MP Cayenne V8 coolant temp sensor.pdf