I finally got the temp sensor, it seems a FAE 1551 will be compatible and so far so good, seems to fit perfectly, no leaks and reads when warm (haven't tried it out on the road yet to see how accurate it is), so I think the cooling system is finally done. I was able to fix the radiator crack after some soldering, seems to be OK so far.
I cleaned the diesel system as much as I could, taking out the fuel sedimentor (I found all sort of diesel color in there from past times) and replacing the diesel filter. It took a while to pump manually diesel back into the system after this, in fact, I tried for a little while and nothing happened, then I used a plastic pipe to try to suck some diesel into the sedimentor and it worked, then I cranked the engine for a few seconds and then I tried manually again until fuel came out clean from the top of the filter. Has been working like a charm since then.
As the white smoke was unbearable, I decided to adjust the timing of the distributor pump a bit forward and it worked great, no more "fog" when I turn the engine on for a few seconds in the garage, it seems to rev up nicely too, which was a bit sluggish before.
I can't wait for a test run and see how everything works in the open.
Also, the Disco is turning 200,000KM, time to do some big maintenance, it needs some love too.
I found 3 pictures in my phone that show the evolution of the Disco, from stock, to lift, to lift + tires:
