I've looked around for something matching my symptoms, but no luck. When things got cold here last week, my 1995 XJ Sport started acting up: the temperature gauge stays around 3/4 most of the time, then drops to 1/2 for a couple seconds, then back up to 3/4. I just checked under the hood, and I was low on coolant, and the upper radiator hose was hot, while the lower hose was cold. The radiator didn't seem hot, although it's damned cold out and I was driving pretty quick.

I do have interior heat - no fan, but that's another story - so no blockage at the core.

Once I get everything filled back up with coolant, it seems like the next thing I should check is the radiator, yes? It seems to me like the radiator is blocked, and not allowing coolant through. No idea why this didn't start until it got below freezing, but that's what the symptoms mean to me.

Any advice?

Which list is shorter, with regard to cooling system maintenance?

What u have done?.......or what u haven't done?

Fixed. Air bubble, burped and filled and burped and filled and all is well.

Read my sig, and the cooling system will never be low again. The cooling system is self-burping IF the cooling system is kept full of coolant.