Swapped out the thermostat with the 180 degree one. What a huge difference and a happier Disco to boot. Previously I was around 195-197 highway and 201-206 at drive thru. Now I'm running in the high 180's on the highway and 195 at drive thru. Now, on to figuring out these pesky codes.

 

I think the inventors of the scanguage and ultraguage must have also started a 180 T stat company. I did the same a couple months back, big difference. Very happy. did you put in purple ice? I did but not sure what it's effects were since it was all done at the same time.

 

What is purple ice? Never heard of that..

 

It's an additive that is supposed to help the transfer of heat from the metal of the engine to the coolant. I looked into it and all of the reviews I found showed no measureable improvement in cooling system performance. Here's a thread about a similar product with some links to reviews and a chemical analysis of the product: Truth About Redline WaterWetter(R) - RX8Club.com

 

It reduces surface tension, that's all it does. Allows a better transfer of heat like duxlr said, it works if you have a good cooling system.

 

Purple Ice® - Radiator Coolant Additive | Royal Purple