04 legacy overheating

[04np]

just got my (new) car back from the dealer.. had a CEL for misfiring on, they replaced spark plugs.. i just got back from vacation and drove about 100mi on the highway.. around halfway i realized my thermostat was all the way to H! blasted the heat up, and it slowly went down to normal mid-way levels but I had to keep the heat on or it would rise. started to go down when i got to the toll booth when i was sitting still even though the a/c was blasting cold air at that time.

/shrug
Oil level is fine, look an okay light brown color doesn't smell bad, coolant level isn't low, it's actually significantly over the line where the manual says it should be full.

2004 legacy non GT 5spd

[blackfang]

Being they just flushed the coolant, make sure there is no air pockets, etc.

How much farther over the high line is the coolant?

Also how long/far have you driven since the T-Belt was replaced?
All short distance trips?

Check to make sure they plugged both cooling fans back up being they should have removed them when the t-belt was done.

[04np]

thanks for the reply..

1. how do I check for air pockets?
2. about 2 or 3 inches over the fill line
3. timing belt was changed 2k miles ago by the place i bought the car from
4. i've only filled the tank up 3 times and haven't even finished the 3rd tank yet. about three or four trips have been 80 miles, but beyond that mostly driving through town.
5. both fans are spinning

it only overheated at highway speeds.. on the way home from work and a trip into town just now it stayed fine. granted its not 94 degrees out anymore, but this isn't the first time i've driven on the highway in such heat

[Dookie]

A worn out or broken thermostat would cause this issue as well. Did they change the thermostat? If not, you may want to check that too.