I had my motor running at idle in my garage and then the rad blew up the motor still turns over and has good compression but dosent start how do I know if it overhaeted and blew the motor

 

Depends on how long it was running before you shut it down
Have you done a compression test ?

Is it getting fuel,and sufficient spark ?

 

perhaps you could hook up a temp gauge and run it again. see how fast the temp rises. you'll know if you blew a coolany seal

 

camt find the adapter I need to run my aftermarket temp gauge

 

my car did the same thing i have been trying to figure out what waswrong it overheated while idling but it still starts just overheats about ten min later i thought maybe it was a bad radiator if anyone has ideas to help both of us please help. i also foud a little piece ofrubber in my radiator if that means anything.