SeaFoam will show that leak ... and kill mosquitoes for some distance.

 

Nate, how about some information, how many miles on your engine, when was it last serviced and tuned, did you hear the electric cooling fan coming on when you were driving?
I also disagree with Spike. Our temp. gauges reaches the normal position at apx. 150 degrees, 30 some degrees before the t/stat even opens. It does not move from that position until around 230 degrees, give or take a little, so yes, once your gauge starts moving, you are already in trouble long before the gauge is near the hot or red light area.
Do you have access to a scanner with live time readings, if so hook it up before you drive again and get a couple sets of numbers, temp while city driving, 3 to 4 minute idle temp and highway temp. Also if the gauge does start to move, turn on both heaters to max and let the engine idle back to norm, never turn if off as long as you are not dropping coolant.
Gets those numbers for us so we can help you.

 

Seems like there is more difference between a D1 and and a D2 cooling than just the radiators.

If AC is turned on, a D1 brings on the electric fans. A D2 does not under certain conditions.

If the AC is off, the D1 brings on the electric fans when coolant hits 212F. So does a D2.

Just another reason to own an Ultra Gauge. And maybe re-wire your electric fan relay to also follow the AC. Slow roasting over waste oil drained from other trucks....

Note: I edited this because I first looked up the values for a D2, but was on the TD5 page by mistake.

 

And turn on the heat full blast and drive under a light load.
The heater will blow off heat and driving under a light load will help air flow through the radiator, especially if the fan clutch is weak.

 

I wouldn't hesitate to check the trailer, too. It doesn't take much for a trailer to go from an easy tow to a pain in the #($!. Does it have a bearing issue, dragging brakes, poor balance, mis-aligned axle(s) etc? Does it even have trailer brakes? It's nothing to find a trailer that's been sitting with brakes all but rusted shut depending on what kind of care it had.

I'm now convinced the 180 degree thermostat should be done when you rebuild the front driveshaft with serviceable u-joints AKA as soon as humanly possible... This brought my temps from 221 idle with heat to 197 idle with both AC going...

 

the tires were a little flat on the trailer, i was just towing it to the lake (~4-5 miles) to test drive it.

 

A little flat can be a lot more rolling resistance...

If it were me - flush, +cooling additive with new 'green stuff' fluid and 180 degree t'stat.

If you were putting off trans service, you might want to at least check your level and general fluid condition.

 

Not to hijack the thread, but its been about 112+ everyday here in AZ and the tuck has been running about 204-212 while at idle and both AC's running up from a normal 194 flat. Is this something to be worried about or expected in the extreme conditions in AZ?

Help I appreciated

 

Just because the electric fans come on at 212 does not mean Rover thinks the engine is to warm.
Rover says the engine is to warm when the temp reaches 230+, thats when the temp gauge is at the top of the "normal" mark, 240 is way to hot and the red temp warning comes on, 250 is boat anchor.
I would not worry about my engine temp unless it reached 220 and then I would turn off the a/c, slow down if on the highway and turn on the heat.
If you have complete coolant loose then you must shut the engine off.

 

I like the design of the D1 with two electric fans, perhaps those D2 owners in extreme areas could add a second fan if cooling at idle and slow is a problem. But if you are on the highway, once you get to 204 the stat is wide open, and the water pump and radiator square inches become the limit factors. Unless you put an aftermarket oversize fan on, even then the change would be slight compared to the 50 mph breeze through the radiator from forward motion. Obviously a clean rad without sludge or calcium buildup or bug and mud plaster is a plus. The 180 stat is great for overall driving, but you will warm up from there when slow because of air speed and size of radiator, which the base temp does not change. How long it takes to warm up to 212 would be changed, by starting at a lower temp (driving and then stopping for drive thru, etc.).

And if we agree that 220 is too warm, and 240 very bad.... all the more reason to buy an Ultra Gauge - since Rover temp gauges are "optimistic" by design.

Also, in the summer, you can run cooler with just water and Water Wetter, as compared to 50:50 coolant mix. See http://www.dual-star.com/index2/Serv...tech_info2.htm. With a 15 PS cap, water would boil at about 250F, and we certainly are not running there hopefully.