I just installed the Qmax coolant reroute and the coolant temp sensor does not move up in temperatures. Ive read that the sensor grounds to the housing so I did not use thread tape for the threads but it still does not display temps properly. I also did read that rtv also does not allow for a ground but I had to use rtv for the housing and to attach it to the engine. Could it be that I used thread tape on the plugs/ barb? (I have been trying to figure this out for 3 days now lol)

 

My guess would be the RTV (although the bolts could provide a ground path). Take a piece of wire, wrap it around the sensor so that it touches the metal body, and hold it against the engine block. See if the gauge works.