Recently I replaced my water pump, and clutch fan with new severe duty units, I also replaced my radiator with a new unit. Have been driving it just fine without any heat/cooling issues what so ever. Except after I shut the engine off I hear a knocking type of sound. I opened the hood to see my upper radiator hose bounce along with the knock. First I thought an air bubble so I did the burp process, no difference. Then thought air bubble trapped under the t-stat, so I pulled the 195 out and drilled a single 1/8" hole in the flange and put it back, re did the burp process. Still getting the knock sound along with a "boiling feeling" from the upper hose if I squeeze it a little when its cooling down. Temps are all still fine, coolant seems to be flowing like it should, overflow bottle works like it should, heater is fine, no visible leaks. Today I ordered two new t-stats a regular flow 195, and a high flow 195 without bypass holes as a shot in the dark but I have no idea if they'll help any. Any thoughts on this?