Mine cracked last year, and I bought the entire replacement hose from the dealer for about $120.00 or so. The replacement is actually 2 hoses, including the tee, and takes about 10 minutes to install. I opted for the entire hose instead of a repair kit because mine had disintegrated and I was worried some of the old hose would migrate into the radiator or heater core, get stuck and cause some serious headaches. I flushed the system, and replaced the upper and lower rad hoses at the same time, along with the serpentine belt. As for the opti, unless the water pump is leaking, according to many posts here, leave the opti spark alone. I got a spare tee, by the way, in a junk yard, and keep it in the hidden compartment under the rear most seat, just in case.