A required add-on fitting when retaining OEM coolant feed to a K-Tuned swivel T-stat housing. This fitting is typically not included with a K-Tuned billet swivel T-stat housing.
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 this K-Tuned re-circulation 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 bleeding.
For use with billet K-Tuned swivel neck T-stat housing.