Good morning @PeterB ,
This is intended functionality of OpenRemote. What is happening is that the asset type of the Car Asset, that is the asset type of the assets that the fleet integration makes, has very specific and limited predefined attributes in it (which doesn’t, for example, include Coolant Temperature). This means that you cannot use “any of this type” for rules, or insights widgets, on any attributes that are not currently defined by the asset type that is used.
You can find more documentation about this in the wiki. There was a discussion about custom asset types some days ago here.
Hope that helps!