Ferdman...I don't know the brand I have now but am going to go buy a Behr T-Stat (79c rated) tomorrow. I think this is an MB waterpump from what I can tell. One thing I did notice is that I don't have all of the pressure in the upper radiator hose that I had before with the old engine. I can feel the water flowing through it and it is hot like my other one was. The auxillary fans are coming on at the right temp with A/C on and at right speeds. Unless you went and drove it for a long time and then stopped and idled for a while, you wouldn't get the needle rising (I tried to just sit there today for a long while and it just stayed above the 80c mark). Could I have a water temp sensor issue misreading the actual temp? After the T-stat opens, does it just stay open while hot or does it vary? I'll try the new T-stat first as it did improve a little when I replaced the one in there with my old. Could the fan, with a new clutch not being as close to the radiator, make a difference (it's about half an inch loser to the engine now).