I know this subject has been touched on a lot but here's my 2 cents. I have a history with Jeeps for around 30 years and I have always liked them to run cool. My Rover history is relatively short and has been trial and error. I did not realize until I picked up a UG just how hot they actually run. After hours of research and replacing a leaky radiator I decided to try the grey 180 thermostat. The grey thermostat fixed the problem. 185-187 at highway speed, idle tops out at 194. the highest its been is 197 and that was lugging up a long (7 miles) steep (4000 foot elevation gain) gravel road. There doesn't seem to bee nearly as much fluctuation in engine temp as there was when it was running hotter. I also flushed the system and switched to green antifreeze. I got a couple codes (O2 sensors) while the system was getting used to running cooler but they seem to have taken care of themselves. I would highly recommend this mod. Its quick and easy and doesn't require modification of the whole cooling system as some of the in-line thermostat mods do. I got my thermostat from Lucky8, $80 delivered.

 

CONGRATS! Another satisfied Disco and Disco owner!

 

yes, the cooler thermostat is the way to go. The only issue I have with mine is sometimes it will throw a code for "engine running too cool", but that is a once or twice a year error message