Understanding my temperature gauge?

[nickyg]

O.K. So I have been listening to some of the old podcasts and reading the forums. I’ve noticed a few people having a temperature problem. So I’ve starting watching my gauge. On my way home tonight and with the ambient air temp at 43 My XJ ran at the first hash mark. In the summer when it’s about 90ish I run a lil over 210 a lil bit more when I stand still.

So my question is... What temperature is the hash marks? Is it running too cold? At what point do I pull over and shut it down?

It has the stock rad. I'm unsure of the water pump and the thermostat. Never touched em in the 4 years we had it. I did put in a new eletric aux fan. (it was making a funky noise) and I replaced the fan clutch.