Well, about 6 months ago I moved to Hawaii and shipped my Turbo. I recently noticed my coolant level slightly low in the reserve tank and ordered a bottle of Pentosin coolant and added some. So last weekend, I was stuck in traffic for over 2 hours on H1 and noticed my temperature gauge (normally at 180 and never seen it go over that) start to creep up to my estimate of 195-200. As soon as I started driving again, it went back to the normal 180. I did notice a slight smell of coolant when I started driving.

I checked the coolant when I got home, and it was fine. I checked that the rear deck fan is running and it is working properly. Also there are no leaks or anything dripping from under the car and I checked all connections and the front radiators and the reserve tank for leaks.

So, am I being slightly paranoid or could the thermostat be sticking? Now I did do a search and was thinking about raising the rear end up, and revving it to try disperse any air bubbles that could be in the system. Thanks for any thoughts.

 

First of all I'm going to assume that you have mixed up your terminology and have not actually put pentosin in the coolant tank and actually put in the Porsche approved coolant. Pentosin is only for the power steering and clutch. I haven't had the issue you describe in my 996tt but have had similar issues in my other cars. The last time I had an overheating issue in one of my cars it was due to a failed water pump. The temp would rise and come close to overheating when I slowed or came to a stop and go back to normal during freeway cruising. When I came to a stop to check water was boiling out of my expansion tank and a leak coming from directly under the water pump. If this isn't happening probably not a water pump. It is also possible that the radiators are getting plugged up. I've also had this same issue due to radiators going bad. These cars are getting older so this could be a possibility. Also Lots of gunk and debris collect inside the front grilles. If you take the bumper off you can clean this all out properly. To a lesser extenct you can take an air compressor with the bumper still intact and blow some air in there to get a good portion of the debris out. Thermostats I've found usually fail open and will cause the car to never warm up properly. I guess the opposite could happen and cause the situation you describe. Just some thoughts to look into. Good luck

Edit: Actually I just looked and noticed Pentosin brand does make coolant so guess I was wrong there.

 

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Hawaii is most likely a bit warmer (ambient temp) . My 996 used to run that temp all the time in the summer ( between 190-195 in stop-start traffic ) in California, had all the crud cleared out, everything worked perfectly fine. Your 996T has 3 radiators so you are maxed out on that .The alternative is to change to a lower temp thermostat , like 165 degrees instead of the traditional 180 degrees..

 

Temperature is going to creep up a bit when you sit in traffic on a warm day. The fans behind the radiators only do so much.

Have you cleaned the debris out from the radiators lately? It's pretty easy to do, and an amazing amount of junk accumulates in there.

Jon

 

I think it's fine as well. I've noticed mine creep up a bit, same as you describe when sitting in traffic on a hot day. As soon as i'm moving again it goes right back to where i expect it to be. Not to mention sitting in traffic for 2 hrs is quite a lot of time.

 

Thanks everyone, I already feel better. My only concern was that the entire time I lived in Maryland (and it gets hot there), I never saw the temperature get higher then 180.

I will check the front radiators to check for debris and clear some of that out. Luckily I have the Techart front bumper, so I can just use my shop vac to clear the stuff. Thanks again everyone.

 

A lot of junk accumulates between the radiator and the condenser. There are just a couple of screws holding them together. It would be nice if you could get that with the shop vac without removing the bumper, but it's not such a big deal to remove it. You should look into putting screens over the inlets.

GL,

Jon