My FE runs at 85C to 90C, both
oil and water, pretty much regardless of the outside temperatures. You should be concerned with your FE's temperature when it is abnormally high as compared to what it usually runs (as opposed to absolute numbers). Some guys over on the FE Forum are comfortable with 225F on a hot day and have been for decades of driving. But for me, the only time my needle has ever even gone close to 100C was when there were fan problems.