so when i start the car in the morning its cold, gradually the temp builds up as it starts running as it does...

anyway the temp guage gets up to about the A mark on normal (its an ef and has an xr cluster)

sometime it doesn;t move from there, running fine no dramas.

but other times (say once or twice a week) it will get to A, and then push right up to O or R before dropping back down to A and running fine the rest of the day. This is just normal driving, shifting as 2000rpm as you do.

i thought maybe the head gasket was going but oil looks fine, doesn't blow smoke, took it to the mechanic for a service and said it was tip top.

so what could be the problem? just a faulty temp guage? ot something more serious?

i think there is a small leak in cooling system because water levels drop a bit over time (as in have to fill up the radiator a little every month) but no obvious leakages, nothing on the ground when the car is parked all night.

so i'm confused as f**k over what it could possibly be.

any ideas would be great, i was worrying myself over having a BHG but apparently it is in great working order.

cheers

The temp gauge jumping up to O or R and then settling back down may be a sticking thermostat. My NF climbs into that region during the hottest summer days but settles back to A or L once I pick up speed or the thermos switch on high speed. My NF is also slowly leaking coolant. I have identified a few places. The rear of the water pump where the steel pipe connects in from under the exhaust manifold (dripping onto alternator). The thermostat housing where the steel pipe connects in from under the BBM. Also at my lpg converter (dripping onto rh eng mount)and the tee piece near the heater tap that runs to the lpg converter (dripping onto sway bar). I have decided to replace my engine and address all the leaks whilst doing the engine swap.

If you walk close to my car when it's hot, you can smell the coolant. Also can see the white/green residue from the coolant. Top my tank up about every month.

sounds alright i guess, sypmtoms seem very similar.

will continue to monitor coolant levels and get around to replacing the thermostat

cheers