Dazed and Confused
Join Date: May 2012
Location: Upstate New York
Re: navi heater booster
Sounds to me like your water pump is wearing. A booster will help solve the rear heat problem, but you may be looking at a bigger problem down the road. Also, you'll want to keep the pump relatively small so that you don't over drive the system and/or rob coolant from someplace else.
Ever notice that there's so many high performance parts available for GM products?
Did you ever think that maybe they NEED them?