Overheating

Hi,

Sounds like you have an air pocket in the coolant. It could also be a cooling fan issue but it appears you have electric fans so increasing RPM does not affect your fan speed.

Here is a video of a funnel that I use to get all the air out of the system. Set it up as shown in the video and then bring the RPMs up so it works the air pocket out. You will need to keep an eye on the coolant in the funnel because if there is an air pocket, once it works out, the coolant will be sucked down into the radiator to fill the void. You just want to make sure you always have a little bit of coolant in the funnel so it doesn't create another air pocket. This is unlikely but could cause this to be more involved than it needs.

https://youtu.be/CFZ9IM-OZOk