The first time my 00 s2k overheated was within the first week after buying it from Carmax, the car was very low on coolant. They did a coolant flush and all has been well (except for the copius amount of white smoke that comes out of my tailpipe when pushing the accelerator full throttle).

Tonight I was driving home top down and it was a little chilly so I turned on the heat. After a couple minutes it still wasn't coming out warm so I turned the heat all the way up (not the fans, just the temp).

Still wasn't coming out warm after more minutes passed. I was about 3 miles away from home when I glanced down and noticed the engine heat was at 4 bars. Then it went to 5...then 6!!!

Still had the heat going but it was still coming out cool. I'm coasting my way home and I decide to turn the heat off. Then all the sudden the car slowly cools back down to 4 bars. I pull into my parking space and pop the hood with the engine still running. Doesn't feel abnormally hot anywhere, I also noticed the coolant overflow bottle was half full.

I then turn on the ac and the car immediately cools down to 3 bars.

What's going on? I don't think I'm low on coolant, but tomorrow I will take off the cap and make sure I can't see any fins of the radiator.

Kinda ironic how turning on the heat really did turn on the heat!

 

Typically, if you don't feel any heat there's no hot water getting to your heater core. Many times it's simply because you don't have enough water in your system. Turning on your A/C in this case would actually make your car run hotter (more load) Turning on your heater typically, if any water is getting to it, will cool it down some (heater core is basically a little radiator. If your water levels are ok, it's probably your thermostat sticking.

 

air bubble

did u bleed the coolant properly after changing coolant ?
i bet not

 

I didn't change the coolant, Carmax did. If they hadn't bled it properly then surely I would've seen problems sooner than a year later.

 

Bad thermostat? White smoke out of the exhaust worries me though. When I had the problem you are describing in another car years ago, I had a cracked head.

 

Well must have been an air bubble. Drove it today for over an hour with no issues. So now I just can't turn on the heat.

Ah well, it's summer.

 

you say you get a lot of white smoke out the tailpipe whenever you get on the throttle? That means you're burning coolant. I would say cracked head or blown head gasket, which would explain why it was low on coolant when you got it from Carmax.

Carmax sells some real POSes some time. It sounds like its too late for you to return that car however. A coworker of mine bought super low mile 06 Camry from Carmax a few months ago, took it to a private shop to get checked out and found out that the car had likely been in a flood and definitely had the transmission replaced already. Carmax will really try to slip some stuff by you. He was able to return it because it had only been a couple days. My neighbors once got a really nice Integra from Carmax once and then later someone with a good eye (and a magnet I think haha) noticed that the entire passenger side of that car had been wrecked and repaired. The entire side of the car was pretty much bondo. It was a REALLY good job, but there had been no disclosure of anything like that from Carmax. I really don't believe in their 100 point inspection or whatever they have.

 

White smoke indicates coolant getting into the combustion chamber(s). With coolant going there, that is probably why you are low in coolant.

Ahh, deathsled got in just ahead of me with the same diagnosis!

 

let us know what you find out about your problem.