different brands coolant can be blent to use

I heard it from a mechanic.
is it right?

no its pointless... mabie they are talking about mixing it with water for better cooling... but mixing diff kinds of antifreeze dosnt do anything.. it could contaminate ur system

You shouldn't mix different types of coolant with one another. The green stuff should not be mixed with the long life or Dexcool style antifreeze. However, Prestone Extended Life antifreeze can be mixed with anything as it has been manufactured to be compatable with all types of coolant. Be sure to check the bottle to insure compatability before using any type of antifreeze.