Subaru Owners.... I've found a lot of you cats have VW's... And some of you are smart thinkers... So assist me!
GF Has a 2005 Jetta GLS
P2181 is a Cooling System Failure code.
It indicates one of a few things: Radiator Failure, Water Pump Failure, T-Stat failure, Engine Coolant Temp Sensor, or Fan Failure.
Here's my objective data:
Inside the car, the water temperature slowly goes up when I warm up the car, and sits at the 190 degree temp it's supposed to.
At idle, the fans do not turn on.
The Fans do turn on after a highway drive. And the t-stat is a 195* t-stat, so it tells me that the sensor, t-stat, and fans should be working.
The engine doesn't take an abnormally long time to warm up, which to me means that the t-stat is not stuck open.
The temp gauge doesn't go above the 195 level with a decent highway drive, which to me means that the t-stat isn't stuck closed.
The coolant reservoir is filled, and the coolant surface is slightly moving which indicates to me that the water pump is moving water in and out.
There isn't any visible leak in the radiator, and the coolant level is normal.
I feel like I've covered all of my bases. First thing I'll probably replace is the temp sensor, because from my research it sounds like there is two parts in the same sensor, and I might be getting a good dashboard reading because the sensor is able to tell me that, but maybe the other part of the sensor has failed.