I recently had a great little go around with my cooling system after it my 99 XJ Sport overheated. I ended up completely replacing the radiator, t-stat, t-stat housing, electric fan, and some hoses.
I don't know if this is a huge problem or not, but my temp fluctuates between 210* and back down to the immediately lower hash-mark.
My assumption is that the new radiator is doing its job really well and bringing my 50/50 mix down to a nice, low temp.
But... when I let it idle for a little while, the temp goes up to around half-way past the 210* hash mark. The electric fan takes care of it and keeps it there, but I'm a little concerned that this is happening in the deal middle of a cold winter. I don't want to leave it alone and then end up overheating again come spring.
If anyone has any thoughts on this, I'd love to hear em!