Omg this is crazy.

Tighten your hoses and put the shroud on.

Doing any testing without the shroud is idiotic at best. Go no further until you do so. Your fan isnt pulling most of its air through the radiator without the shroud, it's the one most important thing for helping cool. Without the shroud the fan just pulls the air from wherever the least resistance is, everywhere else.
the shroud MAKES the fan pull air through the coolers. Simple. This is ESPECIALLY needed on a rover. You're driving a timebomb.

If you want to see if your rad is clogged, go to the auto parts store and borrow a borescope, shove that down both sides and look at the insides, or, just buy a jug of super flush and go through the motions. I would bet your rad, other than maybe the bottom couple rows, is not clogged.

park the truck on a hill, let the thing cycle, bleeding it a couple times, and see what you're at.
Or drive to PA and I'll do it.

and too the guy that stuck his hand on a turning fan with a fan clutch, it's supposed to do that. When the clutch gets warm it then engages and will not let the pressure from your hand stop it, it will cut your fingers off.

 

Thanks, Shanechevelle. I did have the shrouds installed back after taking the photo. So it is not a concern.

I will have the new reservoir in today. After that I will replace the old one and then find a place where I can park uphill and re-bleed the air and see how it goes. Will let you all know after.

Thanks,

 

Updates -

So I put the new reservoir on with the new cap. Got all the air out I think as I jacked up the front with the highest floor jack I have (couldn't find a up hill parking here). Test droven for more than 10 miles and came back. Engine was fully warmed up with the temperature needle right pointed to the middle. After I came back, I openned up the hood and heard no hissing noise, coolant level is at normal didn't show any dropping. I will park it overnight and checked everything first thing tomorrow morning, and then give it a longer drive test.

 

Glad to hear the shrouds back on.
Do you have a temp gun? Do you have a obd2 reader that shows live data? You really need a temperature monitor like an ultra gauge so you can watch the temps and see what the truck is doing.

 

So, the new reservoir and the cap on for almost day. have been on several trips in and out, no overheating in redzone so far. The only problem was that I couldn't drive on the higher speed. anytime when I got on the highway at the speed of 60+mph for more than 5 minutes, the temperature started to move up, the temp needle got close to the 3/4 white line. I wasn't sure if it would go all the way to the redzone as I didn't continue to drive. When I got off the highway and kept the speed below 60, the temp came back to normal at the middle. I checked the everything, no coolant leaking, no sucked in hoses, both fans were working properly.

I didn't have a infrared temperature meter to check the radiator temperature yet, but does this seem to be a problem with the radiator that it's not efficient enough for driving on the highway when the engine is at higher RPMs?

Thanks,

 

 

I think you have diagnosed correctly. If it will idle all day, or do short low speed trips with no sign of overheating, but overheats on the highway, that is likely a plugged radiator. I have had a couple trucks do this and a radiator swap took care of the problem.