ragerard

Driving my new GT4 from Leipzig to France I noticed a strange quirk. Randomly, the water temp gauge would plummet from 219 to about 180, then rise back up. Obviously, the temp can't change that much so I assume a faulty sensor. Anybody else seen this?

Also, I thought the running temps --219 water, 239-40 oil--were a little high, even for a hot, 80 degree, day. Any thoughts?

All this while staying at 4K RPM or below.

phefner

Should be the 3rd Radiator thermostats opening up. I would see exactly the same in my 991.1 after I installed the 3rd radiator. Since the coolant system is closed, its going to eventually heat back up, and repeat according to how hard your driving.

Seeing similar temps.

venom51

Yep...

ragerard

Thanks guys. Really helpful (and comforting). Funny I never saw that in my 991.2 GT3 (but maybe I just didn't notice).

Pokerhobo

Oil at 230-240F is normal for this new engine. There's an existing thread on this topic and the hypothesis is higher temp to burn all the emissions making it cleaner.

zedcat

Just for info and I am unsure if the 718 is identical to the 981, but in the 981 there is no separate valving/control for the center radiator they are all plumbed together and this is the same for other models with center radiator historically. The 981 GT4 utilizes a Map controlled thermostat- basically a heating element for the thermostat to allow different cooling programs depending on mode, throttle etc. I think it's likely 718 is the same. Anyone know for sure? .

arcamalpha

I’ve not found any way to make it run consistently cooler sadly, despite trying a range of combinations. I’m also a bit skeptical about how the water temp is measured: it drops very quickly at higher revs/loads; much more quickly than I would have thought possible given the quantity of water.

wizee

Yes, the thermostat is software controlled. There was a whole thread about this a while back: https://rennlist.com/forums/718-gts-...-radiator.html

venom51

Must just be a change in behavior in the 981 GT4 when you hit the sport button. I just always assumed they were allowing flow through the third on it and not changing the thermostat behavior.

ragerard

Thanks again. Existing thread really helpful. It exactly describes my observations. Feel a lot better!!