I plan to use a Motorad 439-180 Thermostat based on some research. I just want to confirm that this does indeed fit the Discovery II. Amazon says it doesn't.

 

I put one on my 4.6 and it fit just fine.

 

I will be doing this mod soon also and I was just wondering if the stock gauge actually reads slightly lower or does it suck that much as to show no difference? Either way I'm gonna get an ultra gauge and from what I hear its a necessity along with front driveshaft.

 

That is the correct t-stat



As far as the temp gauge is unreliable, it stays put right in the middle until its too late then it moves very quickly to red line and you can pretty much kiss your head gaskets goodbye. Ultra gauge or scan tool is priceless when owning a disco.

 

The poorly written software does exactly that, keeps pointing at 50% anywhere between a range of "X" degrees to "Y" degrees. This lulls the owner into thinking all is calm beneath the bonnet, when in fact every day for months the truck has been running hotter and hotter. Not like your old detroit iron where you were used to the needle on "M" of "temp" and could see it move to "P". The Rover gauge is in effect a computer controlled idiot light that uses a pointer.

Some one had to approve the specifications, and test the software. The software is in the Bosch ecu. The person who wrote the code was not sitting at the Rover factory. This is a good example of engineering-by-committee problems, and how a very simple problem can have major problems multiplied by Murphy's Law.

Example - SWMBO, who can spot a yard sale at 2000 meters, looks at the gauge. Every time she looks, it is at 50%. All is well, based on what Prince Charming told her. The entertainment system is cranked up to hear a favorite oldie (just push the Flux Capacitor button for that station), and the gurgles under the dash are not heard. So after weeks of a slow coolant leak from something cheap, like the throttle body heater $25 part, the coolant is below what can be used to sustain operations, the temperature has risen to dizzying heights, the head gasket finally fails, the head has warped, and now you have a $2500 problem. Note: speak at a whisper level to SWMBO at this point if you possibly can. It really is not her fault.

One advantage of the Ultra Gauge is that it can be programmed to make an alarm sound when temp gets beyond the range Prince Charming deems important.

And the UG will work for Rangies and D1s, the older gauges were designed for poor operation as well.

 

I just replaced my thermostat with the 180 and my gage didn't move at all

 

It won't move because it stays the between 150 to 330 degrees.

 

It can't - the computer makes it point at 50% over a wide range of temps. You'll need to plug in a scanner or Ultra Gauge to see the real temps being monitored by the computer. Not like the analog gauges in Bowling Green's finest fiberglass.

 

My D2 temp gauge hit that mid-line at 147 degrees according to my Ultra Gauge the other day. It was still at mid-line when I shut it down at 230.

 

Another confirmation of the SWAG programming (Scientific Wild *** Guess). An Ulra Gauge makes a great holiday gift. "Look Honey, I bought something to protect us from a computer weasel at Bosch that wrote this software bug that will kill our truck!"