Coolant flush/replacement.....2006 aveo....questions.

[FlaAveo5]

Ok. JUST found out that where I can take my Aveo to get a full power flush,$111. Uses a 'Universal Coolant'??? Is there such a thing?? I took that Dex-Kill out LONG ago. They say this stuff is an 'OAT' type and it is 'yellow'. Does this exist?? I put Peak Long Life in it about 4 yrs/9K miles ago.

Can I replace the fluid,myself by just taking off the lower radiator hose, and starting up the car to force the rest out of the engine/heater core/radiator?? OR does it have to be 'power flushed' by a pro. to get to the core/radiator?

I am still trying to figure out IF I even have a petcock on my 2006. (Original radiator). Does it have one? If so,where?? I don't see it. IF it has one, will doing it the open hose off way, take care of the radiator as well?? Or only be half-assed?

Thanks all!!!!