T-stat housing obstruction noticed
When changing my t-stat the other day I noticed that inside of the housing (on my '92 SE) there'* an odd configuration inside the engine head that is situated directly in the middle of where the copper pellet descend that comes up like a small step. Not sure if this is normal in all 3.8 VIN L engines or not.
Looking more closely I noticed that because this little section is way too high on the housing floor, the pellet hits which can and might harm the pellet itself. I had a 180 Robertshaw which ran just as hot as a 195 even while cruisng on the highway. After I took it out I could easily see the slight impact marks of where the copper pellet forced down against the hot housing floor before a full open stroke was achieved.
This problem is most obvious on Robertshaw and Stant Superstat models since they tend to be longer in the spring and strut, so I use a standard Stant purchased at NAPA - it'* a good 1/4 inch shorter in design and makes a big difference overall.