eddie

I was wondering if anyone has their car system grounded to their car battery. I have been having a problem with my heater core being 'blown' 3 times already. After the third time the technician said it was because of the stereo system I installed. He suggested I ground the system to the car battery. I've never heard of anyone grouding their system to the battery, most people use the car chassis. And I do believe its true that the system is causing my heater core, before I installed the system I didn't have the problem, and I've had my system disconnected for 3 weeks now to verify that the core didn't leak again and it hasn't. So, is grounding to a car battery something that can be done?
thanks in advance to all replies.