I had to replace the thermostat housing because I kept smelling antifreeze when the engine would warm up. I could not find leak at first but I shined a flash light on the top of engine block right under intake manifold and found that there was a long swath of coolant going all way back to engine block. At first I thought it was a hose clamp or the big hose going to radiator. It turned out to be the whole housing where it bolts to intake. All the sealing system is--an "O" ring on bottom part of surface of goose neck and 3 bolts. Well, what happens when plastic gets hot? It warps. Can't believe how cheap these auto makers can get. They know exactly how long this junk will last when they build these cars!! I guess they have to save money so they can have a big fat pension and retirement. Plus paying these egg heads top brass millions of dollars in wages per year. In the mean time we have to keep these gallopies running don't we?