Just got my Ultragauge for my "new to me" 2004 Disco 105k. I've had it for about three weeks now and I love it! I've put some new tires on her, flushed the coolant and replaced the thermostat,full synth oil and filter change, changed transfer case fluid, performed the induction cleaning with Seafoam, conditioned the leather, and added an SD rack. I'm having a great time with this thing.
Head gaskets were done 800 miles ago, as well as install of new PS pump and new driveshaft recently.

So.. the ultragauge: I drove 250 miles today chasing ducks around NE Colorado and was a bit surprised by the temps I was getting. I was driving blacktop at 70mph and dirt roads in the Grasslands at 30mph and even a few 10 minute idles checking maps and such. My temps ranged anywhere from 215-224 and was averaging aroung 221ish. Outside temps were around 50F today.
The thermostat that I recently installed was the OEM one, not the 180. I will be ordering this tonight. I've heard that it typically drops temps by 10 degrees or so. But even 210 degrees seems a bit high when I read that a lot of you guys stay below 200 degrees.
I'm confident all of the air is purged out of the coolant system. Peak coolant and Water Wetter.Water pump and fan are working.
What other advice do you all have to help me lower these temps?
I think it is the og radiator. So maybe I'll try that this spring?

Thanks in advance
j

 

If you have the OEM 195deg thermostat, you should be right between 195-205. If you're confident your pump, fan & fan clutch are all good then, yes, it's probably a gunked up radiator. (If you have access to a laser pointer temp gauge, measure the difference between the top & bottom of the radiator. If it's more than 10 degrees, the bottom is full of sludge.) Try giving the system a good flush or two, see if that helps. If not, the good news is D2 radiators can be obtained for around $250 brand new.
Good luck, have fun with your Rover!

 

That or cluth fan your elec fans should kick in before then or if ac is on , get motor warm & shut off & check if fan has resistance or free like when motor is cold .

 

Well... I guess I'm not totally confident...What is the best way to check that the fan clutch and water pump are functioning properly?

 

Fan clutch should be resistant to turning when the engine is warm. So after you drive it open the hood and the fan should maybe move 1/4 to half stroke. Should spin freely cold. My temps were like yours and I installed a new one, 35$ on amazon, and temps went down to 200-210. 210 at idle. Installed 180tstat and I run 190 on highway and 194 stop and go. At idle I might get to 198-199

 

Started Disco in the driveway. Let idle for 20 minutes. Temps leveled at 212F. After I shut the engine off the fan spins freely. I guess I will replace the viscous fan clutch when I install the 180 T-stat. It looks fairly straight forward. Is it a pretty easy install?

 

Bingo! Bad fan clutch. Driving at highway speeds won't make much difference, the car's moving fast enough to force plenty of air through the radiator. But idling or around town you need the fan to help out with the air flow.
While you're changing your clutch, you might want to replace the water pump as well. They often fail precariously close to one another, or so I've heard. Not a difficult job, I did mine ('98 D1) in an afternoon and the hardest part was getting to some of the water pump bolts and getting the bolts on the clutch loose.

 

On an 03 or 04 you have to replace the fan and clutch as a unit, or locate a set of 99-02 blades to put on the clutch.

 

Thanks guys!

 

Very straight forward. I borrowed a set of wrenches from autozone to get the bolt off. I think it is something like 35 or 37mm. They have long wrenches to break the torque specifically made for fan clutches.