I just changed the CHT on my 17 year-old's 2003 V6. By the way I am an accountant, not a mechanic. So if I can do it, anyone who can turn a wrench can. There is a lot of misinformation on the web. The 2003's use a CHT, not a Coolant Temp Sensor. It is mounted on the back of the driver side head. So it's a tight fit between the bulkhead and the sensor making it very awkward to get at. I actually placed a small mirror on a selfie-stick and poked around to get a glance at it.
After disconnecting the battery, I pulled off the 3 spark plug wires (mark them first). Then I literally lay across the motor to where I could peer down between the bulkhead and engine, and from that angle you can see it. Removing the spark plug wires gave me just enough space to run my arm alongside the motor and reach around the back, past the last spark plug, and feel for the sensor. So between that and peering from above, you at least know where to put your wrench. Mine had a white plastic connector from the harness.
Press down on the tab to release the connector and slide it off. The tightness of the area allows for 1/8 or 1/4 turns only, using a 19mm open end wrench. Maybe a shorter wrench would have worked better. Anyhow, the sensor has a pretty long threaded shaft, so once you disconnect the harness, it just takes patience to remove. Installation of the new one was easy. Just put a little grease on the threads, and hand-tighten as much as you can before using the wrench. Snap back on the connector and you are good to go. Sorry I tried taking pictures but they hardly tell you anything. I couldn't see paying almost $300 to replace a $20 part. It took me about 3 hours - the longest part was figuring what needed to come off to allow access. Turned out, just by removing the spark plug wires was enough for a guy with fairly skinny arms.
After disconnecting the battery, I pulled off the 3 spark plug wires (mark them first). Then I literally lay across the motor to where I could peer down between the bulkhead and engine, and from that angle you can see it. Removing the spark plug wires gave me just enough space to run my arm alongside the motor and reach around the back, past the last spark plug, and feel for the sensor. So between that and peering from above, you at least know where to put your wrench. Mine had a white plastic connector from the harness.
Press down on the tab to release the connector and slide it off. The tightness of the area allows for 1/8 or 1/4 turns only, using a 19mm open end wrench. Maybe a shorter wrench would have worked better. Anyhow, the sensor has a pretty long threaded shaft, so once you disconnect the harness, it just takes patience to remove. Installation of the new one was easy. Just put a little grease on the threads, and hand-tighten as much as you can before using the wrench. Snap back on the connector and you are good to go. Sorry I tried taking pictures but they hardly tell you anything. I couldn't see paying almost $300 to replace a $20 part. It took me about 3 hours - the longest part was figuring what needed to come off to allow access. Turned out, just by removing the spark plug wires was enough for a guy with fairly skinny arms.