i just got may car out of the shop and had some body work and exhaust it had been sitting for 3 months and i had a new koyo radiatior put in and i was burping the radiatior on i saw little bubbles coming to the top also the motor was rebuilt 15,000 miles ago. is the motor going out?

 

Propably not, do u see signs of oil in the coolant, if not then it's just the cooling system purging the air out.

 

Small bubbles are ok, lots of big ones are not good. Since its been sitting for so long it probably just needs a good burping.