Do i need a new thermostat

Im resurrecting an old thread re my temperature after fitting this
LAND ROVER DISCOVERY TD5 2.5 98-04 LIGHTWEIGHT ALUMINIUM ALLOY RACE RADIATOR RAD | eBay
i have taken the car out on several short journeys and temp gauge has sat under 1/4. today we did tweny odd miles before it got to 1/2 mark on gauge.it soon drops back down to the 1/4 mark.got it home on 1/2 mark plugged in nanocom and it read 73.5 on live data.gauge showing 1/2 mark.took for spin with live data and dropped down to 61.3.went back to 1/2 and nano read 71.3.im hoping i have shifted all airlocks.and i know its the idea of the bigger rad.should i worry or leave well alone

put new genuine thermostat to rule it out then bleed well the system, by the way did you fill it with the tank raised then bled it with revs above 1500rpm as you must?

once the gauge is at the middle if the system is airless and the stat is good it must not drop below as long as the engine is running no matter what kind of radiator you have

it does sound like it's stuck open, doesn't it

why did you buy a new rad?

stuck open or doesnt close as it should...also it's a good practice to put a new genuine coolant temp sensor too every let's say 50K miles cos these NTC sensors even if they dont completely fail they are loosing qualities in time... it might affect fuelling/mpg too without even notice it

Cheers chaps. bled with tank raised,bugger didnt know about 1500 rpm.will replace thermostat and top hose as i cross threaded brass bleed cap.i bought a new rad cos it went with the extra large intercooler i fitted.

it's not mentioned anywhere but as the mechanical bypass flow valve in the stat opens at 1500 rpm it's good to rev it above 1500 while bleeding, do this trick after you refitted the tank to it's position and let the bleed screw partially screwed in otherwise it will spill all over the coolant...then tighten the bleed screw when no bubbles are showing around it

Ok just ordered top hose,genuine stat (ouch),gen coolant temp sensor.and will pick up 5ltr oat concentrate.only changed coolant couple of months ago and done less than 50 miles but hey ho.need to know running ok as towing caravan in 3 weeks.