Blown Head Gasket or Cracked Block

It is an automatic trans but has a seperate cooler out front.

I did a compression test when we first got the car and all cylinders were right up where the book says they should be.
I will do a complete turn up just to see if that does it.
It seems strange that it was running great before they left and when it comes back...the idle is nasty...

thank you

rick