Hasn't actually reached red yet, but after 10-15 mins it starts going up to the 3/4- 5/6's mark. Then back and forth every once in a while. Typically always driving 30-55 mph.
Thermostat just got changed, coolant levels good, fans turn on.

Appears like the temp sensor works normal. Vans old , has like 270k on it. Exhaust leak into coolant passages blocking flow? Not really sure what to do

Most to least likely

Coolant level
Thermostat
Water pump
Fan
Bad radiator cap (pressurized systems only)
Head gasket

What's the coolant look like? Go buy a tester to see if you have any gasses in thr coolant.. If you do, it's probably a head gasket.. Also, check the reservoir, is it full or dry? You said you just changed the thermostat, did you seal it right and tight?

It do this before you changed the thermostat?

novice question

<~~ novice. Only experience I have is whenever something goes wrong with any of my cars and I attempt to figure it out.

Yes, after checking coolant level its the first thing I thought of replacing. The way the temp gauge was acting it seemed like a "sticky" thermostat.

Don't have a torque wrench but I did clean/prep the area and snugged her down good. After thermostat change it didn't change anything. Coolant level is between the min/Max line in reservoir.

is it a factory temp gauge? are there any other signs that the motor is overheating? it could possibly be a false reading unless you know the temp gauge is fine

I agree with JDH, you first need to confirm the car is actually close to (or is) overheating. Don't trust your factory gauge.

An infrared thermometer would do you wonders to check.

Air in the system can also cause fluctuating gauge readings as well.

Was the system "burped"? or purged of air?

This post was edited by OldAndyAndTheSea on Jun 19 2015 02:44pm

Willing to get the head gasket is going.