4.6 hse temp gauge issue

hi all my friend has bought himself a 96 4.6 hse p38, had been sat some time , changed battery and a few service items and all seems fine but the temp gauge is all over the place it doesnt overheat or use water but its driving him crazy ,does anyone one know what would cause it to go up and down all the time? have changed sinle wire coolant sensor with no joy? any help would be great thanks

it rises to red pretty much instantly, doesnt use water?? but hose or rad doesnt feel that hot?? very weird

is the top hose getting hard, if so how hard how fast?

if the car is not overheating for real,tell ur friend to put a cable from neg battery terminal,to alternator body,there is a ground problem.Had the same,till i replaced the sensor,the tstat,rodded the radiator,flushed the coolant and burped it,put a cable from bat neg to alty body,it solved the dancing needle,but till now i am not satisfied from the readings of the temp gauge coz it shows half a mm above middle,and never passes it,but i am paranoic about temperature gauges.every 2 minutes of driving i check the temp gauge,i miss the scenary just to observe the bloody needle.

will try the cable now, it pretty much goes in red straight away , it doesnt boil or use water ,top hose doesnt really get to hard but engine or rad dont seem to get to warm either thanks again

almost every p38 till 99 model i know about,have this cable.the temp gauge on the p38 pre 99 is an untrusty fooker,they have used a single wire,try to ground that sensor when the engine bay compartment is burning hot with higher resistance on the grounds cable.NEVER.

i hate my temperature gauge,I HATE IT.every time i look at it i feel sick,and hear a voice in my head telling me it is going to blow now,it will overheat now,it will crack a block now,it will loose coolant now,pleaaaaaaaaaaaase make these voices go.
cheers

if there was an airlock would this stop the flow how do you bleed the 4.6

as per rave,bleeding is to open exp tank cap,keep a steady idle at 2000 rpm maintain till airlock is gone.
Normaly the cooling sys of the petrol p38 is self air bleeding,and i believe that.
Now if the car is really over heating,then ur friend have onother prob in his hands.