Why is my eagle overheating?

[A-man930]

Flushing any parallel-flow heat exchanger is basically a waste of time.  90% of it can be blocked up with junk without noticeably affecting flow.

If I'm understanding your situation correctly, I bet you've got a clogged radiator.  

[eaglescout526]

1 hour ago, A-man930 said:

If I'm understanding your situation correctly, I bet you've got a clogged radiator.  

Right now that’s what I’m leaning towards as is probably everyone else. 

[watchamakalit]

43 minutes ago, eaglescout526 said:

Right now that’s what I’m leaning towards as is probably everyone else. 

[eaglescout526]

I created a little tool to help me flush the radiator and I want to share the idea. 
 

I took a spray paint cap, used a soldering iron to cut the middle out which is the perfect diameter for a garden hose

 

And the inner sleeve of the cap allows it to slide in to the rad fittings like this

 

Then you can insert the garden hose to the hole you made on the cap and it should help make less of a mess and let more water force in the radiator to get a good guaranteed flush. 

[AZJeff]

I am skeptical of the effectiveness of  radiator flush on a rad that has built up crud over years of neglected coolant.  
 

It’s been my experience that the relatively small long coolant passages in a rad are a bit like advanced arteriosclerosis, where the crud grows upon itself and cements itself in layers, plugging the passages such that nothing short of mechanical cleaning of the tubes will remove the crud.

 

I am old, so I remember when radiator shops would do what was called “rodding out” of an all metal radiator.  This involved unsoldering the tops of the end caps (back when they had metal tanks) and then pushing metal rods through the tubes to remove the crud, and then resoldering the tanks ends back together.

 

This worked well on all brass/copper radiators, but these modern rads with aluminum core/plastic tank don’t allow this type of treatment, and replacement is the cure for plugged passages.