Remove the 2 T-15 screws holding the front air snorkel in place.

Pivot the rear air snorkel out of place, releasing the air box retention tabs (white arrow).

Unplug the single oil filter housing connector by depressing the metal retention clip.

Loosen the two retention bolts mounting the factory flange to the cylinder head.

Using a flathead screwdriver, gently pry the factory hose from the cylinder head ensuring not to damage the head.

Place a drip pan underneath the vehicle before removing the hose, as a large amount of coolant will drain from the engine block.

As can be seen above, the factory o-ring has worn out and become flattened. This flat o-ring can not seal the engine properly and will leak coolant.

Use a pair of scissors to carefully cut off the factory flange from the hose, ensuring a clean and precise cut. The factory band clamp securing the hose is not removable but can be carefully cut off using a Dremel tool if necessary. However, simply cutting off the old flange is an acceptable solution. The factory hose is sufficiently long and can be extended as needed to accommodate the modification.

Fit the new band clamp over the factory hose.

Tighten band clamp around new upgraded metal flange. This new metal flange will future-proof the engine by minimizing chances of future leaks.

Install new o-ring onto the new upgraded coolant flange.

Lubricate the new o-ring by applying a small bead of grease and/or coolant to the outside of the ring. This will help it seal into place without damaging the rubber due to friction.

Align the thermostat to cylinder head flange with the engine block ensuring the bolt holes line up and firmly press it into place until it's flush on the top and bottom.

Re-install the two flange bolts ensuring they're properly tightened to spec.

NOTE: It's highly recommended to replace these bolts as they're aluminum.

With the new hose re-installed, fill the coolant reservoir to it's max level. Do not overfill. Once filled to max, conduct the cooling system bleeding procedure.

With the cooling system filled and bled, test start the vehicle's engine. Allow to idle for roughly 5 minutes while inspecting for coolant leaks.

Good job replacing the thermostat to cylinder head hose flange! Be sure to keep an eye out for coolant leaks that could appear later down the line.