Car overheats only at high speeds
 

My car recently started overheating on the highway only. I took my car in to Firestone and they said that it was a bad warped and leaking thermostat gasket and housing after doing some kind of leak detection.

Is this what is possibly causing the problem? Just making sure because there is so many shady ass auto shops out here.

+1 for not posting in the correct section needs to be moved to performance. Read the forum rules! It sounds like the firestone guys are right. Your thermostat might not be opening up either. Fix it and don't wait till you overheat your motor.

I would get everything flushed out and change all of the hoses. You must replace the thermostat and gasket (please use the Toyota thermostat) This what I did for my 400.

its not the hoses. you can do a flush just for good measures. you have a bad thermostat. i had this exact issue right before i did my timing belt, water pump, and thermostat. the car needed it.

my symptoms: car idled fine for hours on end. drove fine around town. if you really drove it hard and and above 5000 rpm it would spike or climb in temperature really fast and start over heating.

get a thermostat. dont cheap out and get a toyota one. price difference is not that much at all. i have never had good luck with autozone/murrays thermostats on nissans.

I had this problem, i was lazy and didn't burp the system when filling my cooling system. Ended up getting air trapped. The the vapor pressure of air boils the coolant and then that reaches the vapor pressure since the entire system is ideally under the same pressure and it get hot. When you slow down, the coolant flows slower causing less coolant to reach vapor pressure when it hits the air pocket! could be the thermstat too...

Can I resurrect this flippin thing? My LS400 is doing this. Its very agitating. I followed the steps on Lexls.com to properly fill the system after replacing the thermostat and new reservoir. The T-stat stuck and pushed back and cracked my Res, so I put a new one of each on there, and the t-stat is doing its part (im assuming), my res is fine, fans are kicking on, but it still gets to half. I put a Fail-safe in because I was worried about having it fail again. I properly sealed the t-stat housing with water pump gasket rtv. I have no leaks, no funny running issues, just the temp needle comes up a little bit and I panic and turn the heat on full blast and back off it. It ONLY happens when im going 85 on the freeway. I could have the A/C on around town just beating it like a red headed step child, and no problem. But once I hit the freeway at night when its 95 out instead of the 115 during the day, THEN it wants to act up.

I was going to start just throwing parts at it, but I don't wanna do that yet.... Thoughts?