I recently bought a '99 911/996 in Sept. of '11 with 48K~49K miles. This is my first Porsche. Love it. Did lots of research before buying one, and subsequntley after. I have read as many threads/posts on my issue as I can but none seem to be quite what I'm expierencing, so I figured I'd just ask those who know a lot more about these cars.

Normally the temp gauge is exactly at 12 o'clock which is nominal. A slight varience (depending on conditions) is expected. Hot day A/C on etc. I noticed the other day (a warm day 80-85, but no A/C on) that the temp gauge was climbing as I was in city traffic (stop and go) getting close, about 3/4 of the way, to the 3/4 mark, which by my calcs. is 215 (half way between 180 and 250). When I got back on the highway and did normal speeed (65-70mph), it went down to nominal in about 4-5 miles.
It seemed to me that it was getting a little to hot and that the engine compartment fan should have kicked on. However, from what I have read here and elswhere, the fan does not come on until the water temp reaches about the 3/4 mark(215) which it never does, or the compartment air temp is above 175, which I can't tell.

So, bottom line is this: the temp gauge never reaches the 3/4 mark but comes close on warmer days (above 85) in city traffic. Is this OK? I cleaned the radiators as soon as I bought it. I could clearly see there was a lot of leaf debris.

Also, why does the compartment fan come on when the car is first started in the morning and everyhing is cold?

 

Have you confirmed that your radiator fans are functioning? When you turn on the A/C, both fans should activate. You may have one fan that has failed or is not operating properly.

I agree with your thoughts that some variation is normal, especially on hot days in traffic. However, this is something that you want to watch...

 

having the same issue. Interested in knowing what the resolution is

 

Does your A/C stop cooling when it gets to these temperatures? If so, you likely have a faulty radiator.

 

Mine virtually never goes past the 0 of the 180 mark.

 

Clean your radiators! search for this... you'll be amazed

 

I don't know. I have not used the A/C since I bought the car in Sept. I live in upstate NY so have not needed it yet.

This has only happened once before when I drove the car home from VA where I bought it. In that instance, it was a hot day (90+), A/C was on , and got stuck in stop and go freeway traffic for about 40 mins.

Scantu, I did clean the radiators after I got the car back to NY. There was a lot of leaf debris.

 

It could also be a bad radiator fan or fan relay. When my fans failed, my A/C didn't work properly, especially in stop-and-go traffic. My radiators were fine...

 

Mine never goes past the "0" in 180 degrees.

Definitely get it checked out!

 

Unless most " modern" cars where the gauge is nothing more but an idiot light, the water temp gauge on your car shows that actual temperature. Most drivers are not used to that " feature". These cars easily run with the needle on, or slightly over the ZERO of the numbers 180 is slow traffic. That is normal. If you clean the debris out of the radiators and the fans are working ( just climb out of the car, go to the front and you can hear the radiator fans whirling away ) in the front. Only if the engine is really hot will you hear the engine fan blow air into the engine compartment. You can install a 3th radiator of course and a new thermostat that opens at a lower temp. I am in California and never saw the need for that with my 996 C2.

 

Read the thread below. I took a snapshot of my guage before cleaning the radiators and adding the 3rd. it was 97 degrees in Austin this past week and the needle was stuck between the 8 and 0.

https://www.6speedonline.com/forums/...r-car-run.html

 

You need to run your A/C in stop and go traffic. Most DE instructors will tell you to turn on your A/C when on the track to help with cooling.

 

Interesting on running the A/C. I thought the exact opposite. I'll have to take note and try that in stop and go...with the top down this is when I like the A/C blowing anyway! It seems if you're running at a good speed/mph it would just add more drag and heat with no more "wind" going through the radiators?

I just did a minor overhaul and changed out my water pump and went with the LN 160 deg T stat. Along with changing all the fluids, I added water wetter and cleaned the radiators of leaf debris. I go from 4500 feet in Salt Lake to 7100 over the summit to Park City where I live at 6500 feet. It is a good pull and I push the car and have more fun going uphill (less highway patrol) than I do down. Anyway, with the new pump, fluid and 160 T stat, I still get to close to 3/4 when pushing it up the incline. It cools right down on the downhill side though and seems to stay cooler due to the T stat than before. Only in stop and go do my fans go on. The other day it was hot and the compartment fan actually went on even without the key in the ignition after I shut her down. So, I know it does work.

My advice is do a 160 T stat and check your fluids. Perhaps you have too much coolant as a percentage? Try adding some Redline water wetter to see if that helps. And, after a good hard drive let your car idle to see if you can get the fans to come on. Mine go on when my gauge reaches just shy of the 3/4 mark. Also, many advise on getting a new water pump every 7 to 10 years. You may have some broken fan blades on it as they get brittle. If you do the T stat, it is shared labor anyway.

Good luck and keep us posted.

 

With the A/C on the fans always run. The ECU with switch off the A/C under hard excel.

 

Dennis C, I turned on the A/C and both fans turn on, so that's not the issue here.

Brando and kchociej, I hope the needle never does go past the 0. Past the 0 is at the 3/4 mark.

The heighest it went was half 0 to even with the right side line of the 0.

I need to run the car on a warm/hot day without the A/C on. If the temp. starts to up to more than I think it should, pull into a parking lot and make sure the radiator fans are running.