So after resurrecting my disco from the dead last fall/winter we decided to test it out on a 1000 mile road trip.
Problem 1 - AC not working, I think this will be a simple recharge, but the front e fan is a least working, it finally got hot enough to try it

Problem 2 - very very slight vibration around 2500 or so RPM, this goes away when not on the gas, I have a lucky8 front shaft, and two new front axle shafts, could the lucky 8 shaft need balanced?

Problem 3 - going up a pass in 80 degree weather with an elevation gain of 4400 feet, we saw 215 which was the highest, except for a 218 that we saw right when we turned the rover on one day that dropped instantly to under 200. The 215 was for about 2 min, we rolled down the windows and turned the heat to high which brought it down. I have a 180 soft spring, new pump and green coolant with water wetter, thinking the radiator needs replaced

Otherwise it went well, not a drop of fluid ever under it, and 16mpg average highway temps were 185 to 195 on normal flat roads, and a comfortable but hot ride with no AC

 

For problem 3, do you have an oil cooler? My '03 ran hot while I was towing on a hot day, got to 220, and had to really watch it, struggled up hill. That is with 180 degree thermostat. She will get to 200 in traffic, if it is really slow, but normally between 185-196.

I am considering putting on an oil cooler in the future.

 

Problem 1 could be a simple recharge but ask yourself where did the refrigerant go? Could have a leak

Problem 2 sounds like trans mounts. What year is your truck? If its 2001 and under or 2004 and you have a CDL t-case I'd take the front driveshaft out and lock the t-case and see if it still vibrates. That will eliminate the driveshaft.

 

Never thought about the trans mount, those are "cheap-ish" and fairly easy to do, might need to try that, that is why I was looking for opinions!

 

Oil cooler often makes temp readings increase because it puts something hot right in front of the rad. If you add an oil cooler you also have to increase airflow either with an electric fan retrofit in place of the mechanical fan or with grill modifications, or both.

L8 shaft should be pre-balanced.

For your AC, get one of the DIY recharge kits and vet the r-134 with the dye in it. If its leaking that will let you trace where you're leaking from.

Now on your electric fan coming on - you don't want it getting that warm. Fan comes on at 212. If you want your head gaskets to have a long and healthy life you want to keep temps under 205. What's your cooling system setup?

 

the fan only came on when we stopped at the top of a trail we were on. When we shut off the rover, it was at 210, which is where the alarm on my scan gauge is set to go off. We sat there for about 20 minutes, then started it back up to go down, that was when it read 218, which was odd since the engine had been off, I figure it was due to the coolant not circulating because it basically immediately fell to below 200, but I figured it was a good time to get out quick and see if the second fan was on. We have a new water pump (don't remember the name brand but it is the nice one with the solid impeller talked about here on the forum), 180 Land Rover thermostat, new green coolant with a thing of water wetter, and a couple new hoses (not that they make a difference though). I think the radiator is about all that is left, the disco just hates long hills, on all the standard two lane road driving at 60 mph we were at 185 to 195.

 

"Problem 3 - going up a pass in 80 degree weather with an elevation gain of 4400 feet, we saw 215 which was the highest, except for a 218 that we saw right when we turned the rover on one day that dropped instantly to under 200. The 215 was for about 2 min, we rolled down the windows and turned the heat to high which brought it down. I have a 180 soft spring, new pump and green coolant with water wetter, thinking the radiator needs replaced."
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I had essentially the same thing happening to my 2004 Discovery, with new water pump, newly flushed coolant system, new Prestone (long ago, got rid of the red crap), new mod. inline thermostat, with 180 def. F. Chevrolet thermo. etc., so I tested the radiator, and found it to be blocking coolant to some degree ( no doubt from its early life in Los Angeles as a rental vehicle, using mineral heavy water down that way (I am not in California, by the way. Compromised radiator causing excess heat, which worried the hell out of me, for excess heat can quickly kill these engines, causing cracked aluminum behind liners, liners slipping, etc, etc. A new radiator solved my problems entirely, and it now runs nice and cool, no matter the weather.