This is my official test procedure - it has given instant results on more than one truck:

1. With injectors out - drain the radiator, then drain coolant from the block (I pulled the plug-in heater next to the oil filter).
2. Leaving the degas cap on - pull the small hose from the driver side of the degas bottle and cap the hose with a bolt or pen.
3. Have a "volunteer" puff up the radiator with a rubber-tipped nozzle from an air compressor until the cap lets you know it's at max (it won't be subtle).
4. Spray silicone spray (benign to the engine and sealant) into each cup and watch for bubbles. If the cup is at an odd angle, use a video camera (like your cell phone).

Here is an example with an inspection camera:

 

Great! Looks pretty easy and i'll change to ELC while I am at it. Thanks Rich!

 

The cracked cups I've seen you could actually watch the water droplets form and then run down the cup with no additional pressure required.

Adding small amounts of pressure to the coolant system will help you see if there are any cup issues.

 

That is music to my ears. I have a 2002 as well with 163K on it right now and I am hoping to get the same life out of it as you. My miles are about 75% highway and I am meticulous about maintenance and fluid changes. My truck has never seen a programmer or chip either, what about yours? Not saying there's anything wrong with the right tunes but I figure if I am happy without them why do it?

 

I've got a chip from Tony. I put it off for a long time, but got tired of listening to him give me a hard time about it so I tried it out. Decided to keep it since it was more funner.

 

I have the same experience, but I also had a bad cup seal that passed the pressurized coolant test... the air test caught it. Coolant is easier to seal than fuel or air. Think of it in terms of penetrating oil vs. 30 wt.

 

On factory cups, or cups that had been installed later? I wouldn't expect seal issues on factory cups unless it was an early truck that was running ELC.