Yesterday when I drove my 06 turbo s and got stuck in traffic I noticed the temp was starting to creep up past half way and as soon as I started moving it would drop back to half way. To be safe I turned the heat on when I was stuck in traffic to make sure the temps did not go past half way. I checked the coolant level and it was full. The car did have its coolant pipes replaced already. When I got home I looked around the engine bay and under the car and did not see any coolant leaking. Has anyone had this happen to them or any idea what it could be? I was thinking maybe the thermostat could be on its way out. Any ideas would be great.

TIA

 

Make sure your radiator fans are working.

 

Water pumps final on Cayennes on a regular basis. Is your pump leaking or making unusual noises? Also - have your plastic coolant pipes been changed yet?

 

I would vote your water pump from what I've been told is the thermostats if they fail will 1. Produce a check engine light and 2. When fail remain stuck open so the coolant flows still. So if the temp is rising then the coolant isn't circulating...water pump circulates the coolant

 

I notice that too on my 05 CTT. However, after the needle passed the half marked the needle started to come back down. I'm guessing the fan kick on everytime the needle passed the half marked.

 

Once it reaches operating temperature my needle barely moves. It's actually been so steady even in extreme temperatures that I've occasionally been concerned.

 

Now that I am home I will drive it around close to the house and sit and see how far it goes past half. I was in traffic and didn't want to risk hurting anything so as soon as I saw it go a little past half I turned the heat on full blast to and that either dropped it down to half or the fan kicked on and dropped it.

This is the first time I have ever seen it do this. Normally it would stay right in the middle even last year when it was 100+. Last night it was 82 outside so not super hot.



Thank you that is good to know about the thermostats as it appears to change that is just as difficult as the coolant pipes.

The pipes have been changed by the dealer to the metal pipes and as of now I do not see anything leaking where I parked the car or even smell coolant. I was thinking if it is leaking coolant it maybe stuck up on the undertrays but thought I should still smell it if it is leaking.

 

I am in the same boat but I have 06 S. What I notice is that over time, it gets worse. I also have coolant pipes replaced last year and 0 leaks. I am somewhat concerned about driving my car in traffic since that is when I have problems (same as you). How many miles do you have on your car? I have about 41~42k.

My only guess is that the thermostat is going bad. How difficult is it install on your own? Judging by your post #7, it sounds...difficult...?

 

I have 95K, it just turned it while I was driving it and I saw this going on.

Looking at some of the right ups it looks like the thermostat is located where the coolant pipes are so I am sure it would be a fun job.

 

Bumping this back up as I finally had a chance to pull the car out of the garage and put it on the lift. I drove the car around and got it to operating temperature and then brought it into the garage. The car will get to 180 and then slowly creep past it. The fans will then kick on and the car will go back to 180. Now today it is 75 deg outside so not very hot by any means. I put the car up on the lift and took the shields off the bottom and while it was running looked around for leaks and did not see any. The only thing I see is some dried coolant on the alt but very little but I do not see anything leaking out and everything is dry. I pull all the plastics off up top and looked around and again no signs of leaks and everything is dry. Also checked the coolant level and that is normal.

Could it be a temp sensor going bad?

 

I wouldnt say the temp sensor is going bad. From what you described it sounds like its working just fine. If after the temp goes up and then fans kick on it shows the temp going back down then the sensor is working.

Do you smell coolant?

You state you see some on the alternator but dry? that means there is a leak somewhere, coolant will leak then evaporate and stain.

When is the last time you flushed your coolant? it might be dirty with trace's of dirt that might be clogging up your pump and thermostat.

Your temp guage should stay at one point not raise

 

I do not smell any coolant or see anything leaking on the ground. The dried coolant on the alt I feel might be from another time since I was running the car yesterday and didn't see any leaking down or on the alt that it was wet. I want to try and get in and wash it off and see if new coolant appears.

I am unsure when the last time the coolant was flush would have to check with the dealer. It just came off CPO earlier this year.

To flush the coolant on this car do you just drain the rad and fill back through the tank? Is there a bleeder valve on the rad to bleed the air from the system or does it just purge through the tank?

 

As far as doing the flush Im sorry im unsure of where to drain it havent done mine myself. On my other cars ive drained it from the radiator then the block and have blown out the system. Basically putting an airline into one of the hoses to insure all the coolant and crap has been purged.

Did you say you change the thermostat? I would seriously look into doing this if your going to purge the system.

 

I did not change the thermostat. It appears that it is located where the coolant pipes are so it looks like it would be pretty big job.

 

hmm Yeah it is a big job, we bascially have to look at the reason's this is happening with cooling issues
1. Thermostat could be geting clogged with dirt
2. waterpump could be on its way out
3. Not sure if you have the issue with the coolant sock that covers the pump there is a gasket that gets pinched at times leaking coolant.
4. even if its leaking im not sure that would affect your needle rising? how does the level look on the coolant tank?
5.The temp sensor looks ok since that controls your fans and needle level which you said both worked?

So I would go with the basics of what cools it down the thermostat and water pump ALSO how does the coolant look in the tank? dirt or clean?