Just recently my sc overheated on the freeway randomly, even thought it was running seemingly perfect the day before. It still starts and drives but in less than a mile its pretty much overheated.. so its more instant than gradual. So one f the obvious symptom is that its not pumping coolant now i'm not sure if its because the water pump or if it has air bubbles in the system. NOW, if it has air bubbles in the system does it make that bubbling noise from the dash? even though I've only heard it once i'm not sure what that means. I had it diagnosed by a craigslist (i know. don't even say it!) 'mechanic' and he told me it was the head gasket, but i'm not sure if i completely believe that lol. If you have any information for me PLEASE let me know i'm trying to fix it asap. feel free to ask questions!

 

is white smoke coming out of your exhaust? that would indicate bad head gasket
have you checked your coolant level
when it overheats have you opened the hood? does the engine seem hotter than usual?
do you have any leaks?

 

No white smoke out the back when I start it or when it warms up but as soon as it put it in drive and start going it instantly overheats.. But not while idle. And the coolant was topped off. Well it is hotter than usual seeing as it's not working right! And yeah i opened it but just smoke everywhere.. Not sure what exactly was smoking

 

my 1jz sc is doing some thing like yours and its got air in the rad idk bro hope some 1 can help us

 

1st things 1st, check for leaks, cracks, hoses, thermostat, coolant level, radiator etc etc

 

No cracks in the hoses, I replaced the thermostat, the rad flows good but the coolant system probably has air bubbles.. Maybe a bad cap.. Still seems to have some pressure though.

 

Sounds like a water pump to me. If the water pump seals are bad it would allow air into the system and cause a "bubbling" sound in the coolant system.