K-TUNED SWIVEL NECK RECIRCULATION FITTING K-SWAPK TUNED T stat Recirculation Fitting. If you have a street car with deleted heater hoses you can remove the entire OEM plastic T stat housing and mount the K Tuned Swivel Neck directly to your water pump passage for a cleaner and simpler look. If you choose this setup you will need our K Tuned recirculation fitting to allow coolant flow when the T stat is closed. It also helps prevent air pockets from forming in the cooling system during coolant