When we got our current SP, the fan was wired to be on all the time. I had a discussion with Larry at Fan Clutch and he explained how it should work. First, do NOT connect the fan to be on all the time, it's not good for the fan or engine. He stated the thermostats should be fully open as they can reduce the flow of coolant. The fan clutch is actually used to regulate the coolant temp once warmed up. The fan clutch should come on at 195 and turn off at 185. So you need a good (and clean) radiator & CAC and a properly working fan clutch. You also want the big plastic fan blade, not sure exactly which one but Fan Clutch can set you up with the proper one if needed. Also, be advised the fan is designed to work properly when installed correctly, it will work if installed backwards, but at reduced capacity. It's a pusher fan, that is the air is drawn in through the side louvers and the fan pushes air out the back. You can feel it when it's working. If everything is working properly it shouldn't overheat. Lastly, you want the proper ratio of coolant to water. I also run
Water Wetter. I can't say it helps tremendously but it doesn't hurt either. Hopefully it gives a bit of extra cooling when needed.
While doing some other work I changed out the water temperature gauge with an Isspro gauge. It has a 270 degree sweep, so is easier to read and seems dead accurate. I carry a non contact thermometer and check the radiator or hoses occasionally to verify the gauge. I also installed a fan light on the dash. It tells me when the fan clutch is engaged. For whatever reason this coach did not have a fan override switch on the dash. I repurposed the (no longer used) electric lock switch for the fan override. Of course I had to install the relevant fan switch in the engine compartment and run the wires. The way it's set up the fan can be engaged by the override switch or the temp switch in the engine. When engaged, the fan light is lit. I do like the fan light as I like to know what's going on. With the new (accurate) water temp gauge once it hits just over 190 the fan comes on and once cooled down a bit, it goes off. I've seen temps maybe a bit over 200 for a short period but the fan cools it down pretty quickly. I haven't had to use the override yet but it's there if I need it.
My coolant tubes were in pretty good shape but had a little surface rust and in general looked bad. I just dropped them off at my powder coaters to be spruced up. Personally I wouldn't worry too much about insulating the tubes. The transmission in our coach runs pretty cool, now the retarder will drop a lot of heat into the transmission in a hurry and the water temp will rise correspondingly. But it dissipates it quickly as well.
If you are going to get new tubes made, be sure they have the bells on the end for the radiator hoses like the originals.