Coolant Temp goes up when driving

ok I just added a magnuson supercharger on my 01 Tacoma 3.4. Truck was running great before and I have put 300 miles on after and it is still running great. I added an innovate temp gauge with sensor mounted in the upper radiator hose with an adapter. My question is, if I let the truck idle temps go up to 205...strange thing is that when driving temps go up as high as 216. When I come to stop temps will drop back down to 205 or so. I’m sure upper radiator hose is not ideal for sensor location but temp should not climb when driving. Came home let it sit for about 30min removed cap and it had no pressure even tho engine was still warm. Perhaps cap is bad...I’m going to change to a 170 thermostat and replace cap just wondering what others have experienced. Thanks

 

Pulled thermostat and air bleed hole “jiggle valve” was at 12oclock. I’ve read that with it in this location coolant temps could be 10* higher which is what I’m seeing. Installing the urd 170* with air bleed at 6oclock and will report back.

 

So I’m just updating this thread as I’m guessing it may help someone in the future. Since I didn’t trust the location on the sensor for the aftermarket coolant temp gauge I purchased a ScanGauge this morning. After installing the urd 170 I Jacked up the truck about 4” in front and started filling with coolant. trying to help burp the system by squeezing upper radiator hose. I noticed right away ScanGauge was 6-8* cooler than aftermarket. I also noticed it never got above 191* on ScanGauge and 201 on aftermarket while idling for about 15min. Yesterday idling with old thermostat aftermarket jumped to 206. Anyway took it out for a drive and ScanGauge never got over 188* and was as low as 184. It jumped to 191 after getting on it but aftermarket never went past 206. Yesterday cruising on highway aftermarket gauge was hitting 216 with cooler weather and heater on. It would get warmer when moving and cooler when stopped. Today was the opposite. I’m not sure if the new thermostat with jiggle valve at 6oclock made the difference or if the old thermostat was bad. The old thermostat had less than 20k miles on it.

 

Upper hose is not the best place. If summer hits and you are still heating up going down the road. Your radiator my be getting plugged up. With supercharger I would recommend the aluminium champion radiator.