Due to the K series’ original FWD configuration, the factory upper coolant neck points straight into the firewall in a RWD vehicle.

To correct this, we’ve added this new upper coolant neck to our catalog. Our other upper coolant necks have the inlet pointed to the left side of the engine bay. For our 86 swap, as well as others, a right-side inlet is preferable. 

The OEM coolant temperature sensor also needs to be relocated to the top of this housing, and the factory port in the head blocked with the supplied plug. This coolant neck also deletes the upper heater hose inlet by default. For the 86 or other vehicles, the heater core can be routed inline with the thermostat bypass hose due to space constraints against the firewall. 

Note that this right-side exit neck fits RBB (2004-2008 TSX) and RBC (2006-2011 Civic Si) cylinder heads only.