226 Silicone O-Ring, 70A Durometer, Red, 2" ID, 2-1/4" OD, 1/8" Width (Pack of 5) https://www.amazon.com/dp/B000FMWQHI/ref=cm_sw_r_cp_apa_t2ztAbC3B7KVZLower. Right at the very bottom where you can get up under the bumper and see it right there. I had to pull the hose about 8 months ago when I did t-stats and EGR delete to drain coolant since the LBZ don't have a drain. But it did not start leaking until about a week or 10 days ago, just as the weather started to get colder. When I had the hose off before I did not notice an o-ring... It is just a metal snap ring that locks that hose into place on the radiator....