Couple things: These evidently are prone to a coolant leak that is either gasket or crack in intake. Other thing is that bypassing the heater core(s) can be problematic because the flow to it isn't as easily accessible if you want to bypass it. The return is a metal tube that goes under the intake into the back of the pump. Its all doable, just not the two minute job like on most engines. Seems from what I am seeing and reading on here, lots of simple maint can be a pain because the engine sits so far back and stuff is hard to get at.