ajag

Did my third track day w/ the 991S today and overheated near the midway point to end of the last two sessions, finishing them in limp mode. Temp was around 90. Didn't have any issues the last two days, though the temps were only up into the 80s. Any suggestions? No CE lights, coolant level is fine. Thanks in advance!

kosmo

interesting. I witnessed overheating issues twice. notwithstanding that the 991 runs hotter than the 997, but Limp mode is serious . I dont know if its related but the 991 PDK has 2 radiators and the 997.2 had 3. Something is going on. Is you car PDK? do you recall the oil temp.

ajag

Yes pdk, running in sport+. Temps 275-280ish

shizzle

I was tracking on the weekend, and was doing 30 minute sessions. The air temperature was around 93 degrees, but I didn't run into limp mode. I've got a 7MT, I wonder if they run a bit cooler....

Did you check your radiators to make sure there wasn't anything blocking them (in the spring/fall, I get a ton of leaves in there). Also, have you considered the third radiator kit?

Gabe Newell

I had the same thing occur (991 4S, ~80 degrees F). A couple of weeks later, running at similar speeds with 100 degree F ambient, I didn't have any problems. I don't have any suggestions - just another data point.

MayorAdamWest

I didn't have any trouble with air temp around 93 and I was also running the AC and ventilated seats. Temp was 260-275.

Cogito_Ergo_Zoom

Beat on my 991S like a rented mule at a 2-day DE last month here in Texas with ambient temps in the mid-90s over the two days. The car ran at 200F and oil temps of ~240-250 all day like clockwork. No problems whatsoever. Was very impressed actually. I'd actually seen higher oil temps on the street.

I'd get it to the dealer for a onceover if you triggered limp mode.

ajag

Thanks for the input guys. I am having my independent shop check it out tomorrow. To clarify I only went into limp mode on the second to last session, the final session I stayed off full throttle most of the time and kept an eye on the temps, also put it in sport when the temps got up to 275. I may have to do a third radiator, but would like to avoid that as I may only have the car through the end of this season. I'm going up for a 2 day at road america this weekend, temps are forecasted at upper 70s to low 80s so hopefully it's ok. Also, the track I was on yesterday, the autobahn in joliet IL, is a fairly short and technical track, so perhaps the relatively lack of straights contributed? Oh, and the radiators are clear of visible debris.

j080808

ajag, I was at Autobahn with you (different class) in my white 991 (PDK) and my temps were just fine, I was in sport mode the whole time though.

How about the instructors GT3, what a hoot that was!

Good luck at RA, wish I was going.

fbroen

With the lower running temps in Sport mode, probably makes sense leave it in Sport/Sport Plus on the track?

ajag

I was running sport+ the entire time, only put it into sport when temps got higher hoping the less aggressive mode would help keep me in check.

ajag

Yep, Bill was great, showed me a few different (and faster) ways through a couple of the turns. Definitely makes me long for a GT3, haha, but interestingly after having ridden with him I was just that much more impressed w/ the 991 chassis. In the hands of the same driver, there is no doubt in my mind that the 991S is superior to a 997.1 GT3. I can't imagine how much better the 991 GT3 is going to be!

fbroen

Got it. Thought you were in normal for some reason.

LexVan

Watching.

kosmo

I've heard that the car runs cooler in the Sports setting(s) as the ECU adjusts the thermostat.
This was certainly the case when i did a impromptu test on the HIGHWAY.

weird, but it kinda makes sense.