So I take my '95 Z to the "stealer" and ask that they flush my coolant and blow any crap out of the radiator fins that may have accumulated. Today (95 plus degrees) I get home and the temp gauge is on max and coolant is boiling out of the overflow bottle. Any ideas where to start..........its never boiled out of the bottle before but does run hot in this kind of weather. tks

 

stock the fan temps are high enough that they have needlessly worried a LOT of owners. Far as boiling, the fan temps are high enough that if your pressure cap fails the coolant will boil before the fans turn on.

The lower airdam being broken or missing will cause it to run hot.

If the cooling system was dirty internally them messing with it could hav4e caused stuff to dislodge and find a new place to choke flow.

 

And, they may not have bled the air out of the system.

 

I'm going to bleed the air tomorrow after everything cools down, & likely replace the cap too. Fans were on when I got home, air dam ok. I'm running a 160 therm. as ignition has HyperTech program. Wonder if wrong therm. was installed, I know LT1 therm. is specific for that application. I have one on the self, probably replace that too. BTW .......no coolant in oil. or white smoke in exhaust so hopefully not a head gasket issue. Wish me luck

PS: I found several posts on the same subject. My return line is routed correctly to the overflow bottle but will focus on air purge including running heater etc.