2003 Monte SS with 140k

Hit the danger zone on the temp gauge today, got it home and checked it out. Definitely blew the t-stat gasket. Bout 2 weeks ago it overheated on me, all the gaskets were fine but i had boiled off most of my coolant, oil was clean and i tore down to the LIM and didnt see any stray coolant, at that time i replaced the T-stat and flushed the coolant. For the past few months I've had issues with the coolant boiling off, even after a 10 min drive to taco bell, when i stop i can hear the coolant in the over flow boiling.

In spring of 2010 I replaced the water pump, LIM gasket, t-stat, and radiator fans. All of which are holding up fine. I know theres a bigger issue causing this but I cant figure it out.

Any suggestions?

 

block in radiator causing extreme pressure in the system possibly.... i would double check all of the gaskets again if you got it to the "danger" zone. if it were me i would tear it down and take the heads to the machine shop to get checked for flatness and then rebuild with all new gaskets and replace the radiator while i was at it....

 

If the belt tensioner is weak and worn it can lead to your waterpump not performing properly.

Like John says a clogged radiator could be a culprit too. If the lower hose is substantially cooler than the upper hose it may show the heated coolant is not flowing through the radiator, being cooled and returning coolant into the motor. Also read where with the engine running and the tranny in park, you can have someone depress the accelerator while your squeezing the upper hose. Should it stiffen up and become hard to compress this shows the coolant is backing up in the radiator due to a blockage and cannot get past it very quickly and backs up causing the upper hose to become hard to compress.

 

Radiator cap was bad, I feel stupid lol. Atleast it was a cheap fix.