Postby Carfreak70852 » Fri Mar 23, 2018 6:21 am
Can you tell us a little about what you have done to troubleshoot?
First thing I'd check is the coolant level and overflow level. Make sure the radiator is full and the overflow is at the "minimum" level. If that all checks out, I would try burping the system. These VQs are known for having troubles with trapping air bubbles in the coolant system.
If that still doesn't do the trick, I would start looking at thermostat replacements. I'm going to say this is very unlikely as it seems from your post it doesn't overheat until you're on the interstate.
Hope any part of that helps!