619MAX

I changed my valve cover gaskets along with cleaning the egr tube and I got a new coolant hose from the dealer that goes from the hard coolant line to the intake manifold (plenum) and made sure it did not kink so it should have flow. I checked all other hoses and they are connected and the check engine light hasnt come on. It was working fine before I started doing the gasket job and when I took it on a test drive the first time it gradually went up to 25 percent then quickly toggled between zero and 25 percent for a few moments then dropped to zero and since then I havent been able to get a reading even after taking the car on 2 20 minute trips. I have an obd2 scanner that hooks up to my phone and it tells me the coolant reading goes to about 205 degrees after driving around and then it drops down to about 195. Any suggestions?

My first thought was coolant temp sensor but I get no reading on the dash anymore and my scanner shows a reading so idk whats going on, someone plz help! I checked fuses and they're all good...

SterlingMistMax

There are two sensors for coolant temp one just for the guage and the one that tells the ecu the coolant temp . i had a bad connection on mine and my temp would go down if i hit the gas at least thats what the guage said if your looking at the valve cover closest to the radiator its to the right of that and the one closest to you is the sensor for the guage

619MAX

I think my issue was purely coincidental. I went ahead and changed out both of those sensors and the connection was corroded on the sensor that sends the temp signal to the gauge so maybe the stock sensor was still good and just needed some cleaning but I replaced them anyhow and cleaned the plug by sticking a corner of a piece of paper inside to loosen any gunk and blew it out a few times and sure enough problem solved