i have a 99 accord 4cyl 5 speed. the problem is my car only overheats on the freeway, i replaced the thermostat and did a coolant flush in january.
please help the problem is super annoying because i drive 200+ miles a weekend on the freeway.

 

I suppose you've already checked, but are there any leaks?

 

Ya I check every few days for leaks and the overflow stays at the same amount of fluid

 

Is the overheating issue happenning just when your on the freeway, or simply after the engine has been running and come to operating temperature.
If it is the latter you could have air stuck in your system that circulates to the temp sensor when the thermostat opens.
If that were the case you would see a dramatic rise on your temperature gauge.
There should be a way to vent air out of your coolant system.
On my car there is an air bleed valve for that purpose, Im not certain on the layout of your engine but its worth looking into.

 

Where does the temp needle go to? 3/4 of the way up? 100% up? How many times has it happened and how long does it stay up there?

Just looking down the line at problems that arise from overheating.

 

only happens on the freeway, tried to bleed it today but i dont have the tool to do it. and the air bleed valve is back under my throttle. i have a 2.3 vtec.


itll go up to 3/4 and up with my heat off, it stays that way till i turn my heat on

 

Well there are a few things that I would look into.
First, make sure your system is air free.
I dunno what tool your valve takes, mine just has a hex head so a socket or wrench does the trick.
Second, if your still having issues it could be your radiator just isn't flowing enough coolant and the heater core helps just enough to bring the temperature down.

 

just bleed the system and its still doing it

 

Take the thermostat out and run it without it and see if it'll overheat.

Also, keep track of if the fans are coming on and if so which ones.