Coolant System Questions 996 Mk1

Ladies and Gents, I bought my C2 back in January and have been in blissful ownership since. The weather has been getting nicer and I have been daily driving it to work (35 miles 1 way) on the nice days. Been sublime. Yesterday was my first trip in 80+ weather with some StopNGo traffic/multiple stops etc. My coolant temp needle always sat between the 8 and the 0 in the 180 since I purchased the car.. Well yesterday it rose to the very right edge of the "0" and pretty much fluctated there for a while in all conditions. A/C on, A/C off, interstate, sitting at stop lights.. I turned the heat on full blast and the temp came down a little but nothing to write home about. No warnings, beeps, dings, lights, car seemed to run fine. As a precaution I drove to the porsche dealer and picked up the res cap ending in 04 as I had a 00 cap and thought that it might be a good time to do so. Among other things I researched last night that "some" people think the temp I am reporting is normal, others say it is a little warm. I replaced this cap this morning, topped up the coolant from the "min" mark to halfway to the max mark (took about 12 Oz.) performed the bleed proceedure and drove to work today again. The car held steady at between the 8 and the 0 again the whole ride although when I got off teh interstate it went half way into the 0 and hung there. I popped the hood when Igot to work and checked the level etc and all was well in teh world but I did notice that the "bleeder" valve was popped up via pressure on it's own.. no need to pull up on the metal ring.. Is that Normal? Things I am not scared of... No intermix- coolant is clean, oil is clean Fans do come on (def on high setting, not sure on low) Things next on my list Clean radiators, saw some garbage down in the scoops Test low setting on fan? Engine fan (never seen the bay fan run ever) But no warning light for that either. Let me know your thoughts..

This is normal behavior. You need to do your research

With the a/c ON, the fans should come on with the low setting. You should feel hot air blowing if you place your hand on the ground at ~1 foot in front of the front tires.

Sounds pretty normal. but cleaning the radiators if you haven't already is a GREAT idea. I found nearly a 3 gallon bucket worth of debris in mine.

First get a more accurate reading through the HVAC coolant temp hack. Verify both your low/high fans work. I agree about cleaning your radiators. Your situation doesn't really sound abnormal to me. I've seen those kinds of characteristics on many 996's. Some will say something different as the case just because we are on RL. Lastly, if you are uncomfortable with the needle leaning slightly towards the right most of the time in that kind of traffic, get a 997 instead.

Agree with pretty much all that's been said. Mine will stay low like yours when I'm on the freeway and then pop up a little bit in stop and go traffic. I cleaned my rads a couple months ago and the behavior remained the same (and I flushed the coolant). R

Quotes source post: 12169349

Thanks for all your responses. Normal and Common are two different things. I think the best course of action will be cleaning the radiators before I dig too much deeper. I live in a warm climate and am trying to get ahead of a potential issue. Thanks again, I feel better about it, and will continue my Preventitive Mant to keep it running well!

As Alpine said, you should read what the coolant temperature actually is to determine if it is getting too hot or not. If the coolant temp is not exceeding 200 or so, then you don't really have a problem. If you search the forums for more info about radiators, overheating, radiator fan(s), and HVAC control temp readout, (etc.), you will see that the temp gauge is not very accurate, that the radiator fans have a resistor that often goes bad resulting in either the low or high speed going out, that the radiators need to be cleaned, and that fan relays too can go bad. Otherwise, what you are seeing sounds common and similar to what is reported in many threads on the subject. Happy sleuthing.

Search the way to read the actual coolant temp(like Alpine suggested), instead of the temp. gauge on the dashboard which is on MY99. Press top and bottom buttons on HVAC screen to view lots of useful info. I use mine every time I drive just to monitor actual coolant temps.

Quotes source post: 12170047

I have that proceedure written down, and will use it on the commute home today.

Monitored via the climate control display. 103c was the highest monitored in 80deg weather. It was a 2 hours (35 mile drive) in a mix of some of the most ridiculous traffic, and spirited backroad driving. That equates to about 217 degrees F.

For reference, I believe 105 C was the highest I've seen, and that was after idling at a dead stop in 90 degree weather for maybe 5 minutes. Mostly, I could see the temps rise to about 99-100, the high speed fans would kick on, and the temp would stabilize or maybe drop a few degrees.

103 is when the radiator fans goto hi speed, and the engine purge fan turns on.

Cleaned the radiators today. Hopefully it will help keep me more comfortable.

103 to 105C is normal

Actually what is normal is a wider range. From around 180F driving in cold temperature down the freeway to up to 226F, also driving down the freeway, albeit with the ambient temperature at 116F. Also, driving the car hard in the twisties even in midler ambient temperatures (low 90's). However, the coolant temperature can also climb when just driving around a parking lot at slow speeds in 1st gear. At 226F the radiator fans are on high -- the fans switch on to low speed at 212F and then switch to high at 216F -- but the temperature climbs no higher than 226F.

I saw 222 degrees today in traffic with 71degrees ambient.. I guess you can add me to the list of paranoid drivers.. I don't really get it though as none of the others I have ridden in or test driven have run the needle this far.

I was wondering about your total mileage and if you have every replaced your water pump. Worn impeller blades would result in higher temps. Seems like 222 with 71 ambient is getting on the high side. Mine will go to the right side of the 0 on the idiot gauge in stop/go city traffic in 90+ ambient with ac on, never to the 215 mark, and the fans will kick in on low then high and bring it back between the 8 and 0.

You are fine. Temp will move to the right side of zero when car gets hot (er). I've never had needle go far past the right side of 0 on 180 mark, and I drove the car in the hottest weather imaginable.

76 degree drive home open interstate and back roads, still between 99c and 105c. I will look back in the records for the waterpump service. I saw 106c today on the way to work.. Only for a split second but not did happen