2000 GTS over heating issue, my brother Options

[6G96GT]

My brother has a 7th gen celica gts and the temp gauge was raising and lowering kind of erratically. He said it then started flashing a check light and the gauge was all the way up for about 15 seconds. He thinks he blew the HG.

I went outside and started his car. It fired right up and ran very nicely with only a belt chirp noise. I revved it for a quick sec and then turned it off. It only ran for about 20 seconds before I turned it off. I then checked the oil on the dipstick. It was fine, no visual problem at all. Then I checked the oil fill cap and looked under it. It was bone dry. I checked the overflow container and saw a little bit of coolant in it at the bottom but couldn't see if oil mixed with it.

Oh yeah, he reported having no heat at all either when it was running and he had heat yesterday. I checked for coolant leaks and found none and I absolutely didn't smell coolant in his car either this morning when he dropped it off or this afternoon when I got in it.

What is going on??

I DON'T KNOW WHY THIS POSTED TWICE...SORRY!

This post has been edited by 6G96GT: Dec 9, 2009 - 4:31 PM

[nics]

lowering to the point that the gauge goes to cold when driving continously? if thats the case, thermostat stuck open - replace.

did you check the actual radiator if it has coolant or loosing coolant? even the overflow tank has some, it indicates too much pressure so its pushed to the overflow.

does the exhaust smoke a lot?