Hey there, let me start by thanking all who may respond. This is one of my first actual posts, but I've been using this site as a vital resource for my car since I got it about 6 months ago. A very helpful place to be, indeed. Anyways, just a quick question about a possible issue I've been having.
When I first got my JCW, and until I got to the point of using my ALTA Stage 2 tune, my cooling fan would always come on after turning the car off and stay on for quite a while afterward. Even for the first while after installing Stage 2, it would still come on, but as of the last 2 weeks or so, it simply hasn't come on at all. Now it could be the result of a few things I can think of, first being that I live in PA and it's been getting very cold here as of late. Is the fan somehow in tune with the temperature of the engine and turbo to the point that it runs accordingly? Also, I've been running unleaded 100 octane lately (since about the time that I started noticing the fan), which if the adaptive nature of the fan to the temp is a real thing, could explain less need for post-drive cooling in a 45-degree-or-lower climate.
Anyways, that's all I've got for now. Any thoughts are appreciated. PLEASE let me know if I'm completely wrong. I need some peace of mind on this matter.

 

It's possible your cooling fan needs replaced. Our 2010 JCW needed one replaced. I would say it's more likely that it's you're thermostat that needs replacing. Do you have a way to measure coolant temps? It should be operating around 220 F

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Until you have a way to know what the coolant temp is, you won't KNOW anything.

Scangauge, or torque app something...

And yes, my fans usually don't come on when it's colder. You can check them by turning the ac to max cool and listen for the fans to turn on.