more driving and it seems to be just a touch better, Got a new thermostat with Land Rover name on it so maybe that will make a difference...
I have noticed my dash gauge doesn't seem to go as high when I hit 200-207, it used to go above 1/2 way mark and now it stays lower. I know they are not terribly accurate, just sayin...

 

So I located a post in the DII section that basically says temps up to 235 are not uncommon in hot weather, which is what I have been seeing, except I don't get over 220...It mentions that the AEL emissions system likes the hotter temperatures to run right, so maybe I am concerned about nothing (???) With the 2 electric fans now working, they kick in at 220 and do their job. I did have to replace both as they were not working. Still going to change back to a stock 195 thermostat, the 180 that is in there is not a stock Land Rover one and diidn't have the air bleed hole so I added it. It does't have the plastic plug thing in it. The original t'stat had the center black plastic part, has cracks and parts missing. Also the spring in the center didn't seem to move smoothly and was easy to compress.

 

I hear what your saying, keep in mind the DII is a different beast.
A couple of years I had the same heating concern that got worked out but not before trying nearly everything you have. Thanks to the forum I did a mod that allowed me to turn on the AC fans whenever I want. With my UltraGauge monitoring the coolant temp, when I see the temp raising I will turn on the AC fans minus the AC to keep things cool. These days I simple turn the fans on whenever I drive anywhere. You just need to make sure to turn them off or cause it will drain the battery. So far so good.

Your WetterWater / Purple Ice still in route?

 

I added it a few days ago, after I found that the system as full of coolant concentrate and no water. I drained as much as I could and added jus water, there was still some coolant lurking somewhere, Temps dropped a bit driving to work and back. I then added the Water Wetter to the mix that was in there, probably around 10% coolant, I saw tamps drop by about 7-10 degrees which is what the bottle said for water/coolant mix. It did say not to use water and water wetter alone in street cars so I felt better about using my weak coolant mix. I only saw the temp hit 220 briefly climbing a hill at 67 mph, then it dropped down to 215, outside temps were in the 90's. It is possible the fans came on to help. The fan switch option sounds like a good idea, or I will just tie it to the ignition switch and shut it off in the winter.

Gonna try a new 195 thermostat and see how that works first. Luckily I have a pretty consistent drive to and from work for testing purposes. it is about 45 miles each direction with a few hills, and different speeds.

Keep in mind that this is a strange beast, a 1999 D1 which has some commonality to the D2, especially in the emissions area.

 

I share in your journey reading this thread that is now at 7 pages. LOL
Your D1 is in a much better place cause you never gave up, and still wanting to get it cooler.

As a side note if your not using the AC you can disconnect the compressor from under the hood and still have the AC fans running at will by using the cabin switch.

 

I am not what you are after with the 195 t-stat. That determines when coolant begins to flow through the radiator. It doesn’t change the top end of the temp range. I use a 180 because I want my cooling system to have a “running start”.

 

The theory is that the coolant is flowing through the radiator too quickly, not allowing the air flow to extract the heat.. Theory is based on the fact that I have warmer temps at higher speeds on highways vs lower speeds driving through town. First time I have seen this on a vehicle. Plus I used an aftermarket 180 thermostat that may not be up to the job anyhow. I have the new thermostat so I might as well try it and see what happens. With numerous days of driving at different temps, I have a good baseline to compare different theories so why not??? I can always put the 180 back in.....

 

I suppose it can’t really hurt. I am pretty skeptical however.

 

I agree, but nothing has made sense on this thing yet!!

 

Have you taken note of short term fuel trims under highway vs 'in town' conditions? Perhaps it is running lean.