driving home from work today I had noticed my temps were raising, I stoped at a gas station to get some soda for the house and when I came out my temp was at 230. I shut it down and popped the hood. I noticed the overflow tank was doing just that... over flowing lol any ideas would be helpful. I was thinking thermostat. also went to bleed the system and it had a shit load of air in it comming from the bleeder valve

tested the thermo and it checks out fine. bottom of rad was freezing cold while top was hot. any advice would be app

 

Besides the air being in the system, it sounds like the coolant isn't circulating since the bottom of the radiator is cold. If the thermostat is good, can you see the coolant being cycled through the radiator? As in when you rev it up do you see the water move in the rad. By the way how did it act when you drove it back home? Did it start to overheat again? Has it done this before?

 

it did it once before with the resevoir over flowing, and it started to get hot. this would be the second time it happened. Im replacing everything from water pump to thermo to be safe