All of a sudden my coolant temp was pegged at 260F and an alert came on. This was strange since it came on after starting the car up. I tried it later and it was going back and forth in temp (which makes no sense). I tried again in the morning (several hours later) and it was still 260. So clearly, it has to be a bad temp sensor right?

If so, I can't seem to find much on how to replace it. I saw this thread and can locate it, but I don't see how I could get to it from the top. It is way too tight to get a wrench on it. Can you get to it from the bottom or something?

http://www.justanswer.com/porsche/4g...v6-engine.html

P.S. I also have a Durametric. Would that help with anything?

 

There's no wrench needed. Disconnect the electrical connector, remove the plastic clip (it's a horseshoe-shaped clip that holds the sensor in the hole), and pull the sensor out. You will lose some coolant out of the hole. Be sure the o-ring comes out with it, and you install a new o-ring with the new sensor. Get a new clip too, because you might lose the original one when you pull it out.
It is a tight spot, but it's doable from the top.

 

Thanks! I saw those 3 parts go together from Pelican's site (sensor, clip, seal) and what you are saying seems consistent with what I have seen. I think I will give it a go

 

FYI, here is a more detailed writeup:

- Remove the plastic panels near the engine (one one the driver side and one near the dash). They are the ones with the large "+" sign, but I never use a Phillips. I use a slotted instead.

- Get on top of the engine bay since you will be working directly from the top side. The coolant temp sensor is located towards the firewall. It is not related to the two connectors that are side by side towards the driver side.

- Using a small slotted screwdriver, remove the clip. Insert it into the hole with the screwdriver normal to wires (not parallel). Move it towards the wires about 30 degrees and pull it off. I pull on the little nipple.

- There is a horseshoe clip that needs to come off. Pay close attention to its position before you take it off since getting it back on is the most challenging part of this job. Insert a slotted screwdriver between the horseshoe clip and the sensor(actually the housing, but you know what Im talking about). Use this to pop the clip upwards. Go slowly and get a finger on the clip so you can catch it when it comes off. I ordered a couple extra since they were cheap and just in case (probably not necessary).

- Pop the sensor off and fluid will start leaking. At this point, you can either try to jam the new one in or wait til all just comes out and methodically insert the new one (more on this later).

- Insert the new sensor and make sure there is an O-ring on it. It may be a bit tight going in which is a good thing. Put the horseshoe clip back on. For me, this was the trickiest part. Hopefully you payed close attention to where it is supposed to go (its a tight squeeze in there). I don't have any great ideas, just keep trying. I found it best to the side towards the firewall started just a bit. Then reposition it so that it is seated on both sides. Then push down. Make sure both sides are seated properly. Once I heard it click and thought I had it on, but only one edge was one and the other side was twisted and not in.

- Start and test to make sure not fluid is leaking.

*I had to do this twice since the first time I rushed to get the new sensor in while the fluid was coming out. I must have turned the sensor down enough for the O-ring to fall out. So when I started the car, fluid was slowly leaking. So be sure that the new sensor has the O-ring and an is seated properly.

- So far so good, the engine temps are reading min when starting and back to a normal temp after idling for a few minutes. So it seems the sensor was just dead and nothing more major than that. I am getting an exclamation mark on the dash, but I think that is because the connector was removed. I am not sure if that goes away with time, but I have a Durametric so I will reset and see.

 

When mine does that (Cayenne V6 2011), it's a consequence of low coolant level although the car cannot be overheating just after 2 seconds. Have you tried to add a little bit more water, make sure it's above the minimum bar?

 

Ooops, forgot to follow up. It was just the rear trunk not properly closed.

I did have a low coolant light come on once too, but there is a sensor for that so it tells you in a more direct way.