We have a 2002 Dakota 4.7 and have been having some issues. The temp gauge was floating up toward the H more than normal at idle, We verified the fans were kicking in and went to check the fluid levels. When we grabbed the top hose it was pressurised, rock hard. After waiting for the motor to cool we pulled the plug on the base of radiator to drain it and nothing came out. We then released the cap (in the top hose) and a huge gush of air came out. It was pressurized, but with air not fluid. Still no fluid out of the radiator. We thought we had a air bubble in the system and refilled and ran the truck. The truck has run fine for nearly 2 weeks with the temp gauge never going above normal. Yesterday the truck had fluid sprayed all over the battery tray so we are back looking at it. Thought was to change out the thermostat, radiator cap and go from there.
What i did see that i didnt like was white foam inside the oil fill tube. Obviously we have moisture in the oil. What has me stumped is the oil level is not high and we dont have foam on the dipstick.

Is it a sure thing this is a headgasket issue or should we go ahead and change out the thermostat /oil change and try again?

Like i said earlier- the truck has been running fine.