On saturday evening my 2001 4.0 P38 began to overheat on a short 2m journey to the local shops.
As the temp gauge rose to the red the warning light came on but as quick as it came on the temp gauge fell and returned to its normal half way position.
On sunday I checked my coolant level which had fallen slightly, it took around 1 litre of coolant to top up.
After topping up the coolant I took her for a 10m trip and the gauge stayed at its normal position and used no water.
Is this a warning of something about to wrong and if so what should I be looking for.
Had a look in the oil filler and there is no sign of mayo, what should i look at next, poss radiator or thermostat ?

Hi,I have a 2001 4.0 p38 and I had similar,got warm then fine.kept eye on levels all seemed ok,then it happened again.
My thermostat jammed closed so no water circulation,heater went cold and temp shot up,switched it off but too late,head gasket gone,only just gone said mechanic but still gone
: (
I have had mine repaired but lost all confidence in it now,think time for a change which is a shame as it is a lovely car but hay Ho.