4agte water lines to turbo and to heater when running FWD water setup


Mar 7, 2009
Hey guys,
know the basic idea of what goes where into the turbo in terms of oil feed and return but having some issues working out the water setup. I am currently running a 4agte in a ke70 and am using a fwd water setup in conjunction with the 4age/4ac external thermostat housing. Currently it looks somewhat like this ( i modelled it on this picture)

Now i want to run still run the heater as the car will be club regoed and i hate having cars that don't work, but need to know which direction of flow of the water within the thermostat and where to plumb it not only for the heater but for the turbo as well. One of the water lines will be to the block on the exhaust side of the engine to the water outlet next to the oil tap usually used for the oil pressure sender (I'm using this as the oil feed). My issue is that i don't know where to run the other line to in terms of which section on the 4ac thermostat to tap into, and i don't know if the tap on the exhaust side of the block is high pressure or low pressure, as I've been told i want to run from high to low pressure to ensure direction of flow is consistent.
Also is this the point that i run the heater core into? and where do i plumb this back into?

Sorry for the noob questions


Mar 1, 2012
Tee the turbo water lines off the heater hoses. Doesnt matter which direction if you do it like that

Hot/cold lines I cant really describe without seeing your setup, but Water flows out of the Engine from the outlet on the head (just above the alternator tensioner bracket) and flows into the pump from the line that sits up on the engine block that goes into the back side of the water pump. trace where your lines go from here and you will figure out which sides are your "hot" and "cold" sides.


May 26, 2006
S.E suberbs of vic
yes heater lines is the traditional option, doing it this way make it before the heater flow control tap. However if your going to use that bung out the side of the block then that's a different system, going back to your top hose is the way to go.

I have in-line water fitting adapters if you want one.