coolant flush on a warm engine

[99' Powerstroke]

Has anyone flushed their coolant when the engine is warm (not hot)? The last time I changed my coolant I did it at a friends shop. We went to the shop to change the oil in his truck and change the coolant in mine. We changed his oil first to let my truck cool down, and I'd say between his oil change and draining the coolant from my radiator into one gallon jugs, my truck was probably sitting for about an hour before flushing it with a garden hose. I was trying to let it sit longer to cool down even more, but my friend is always pushing to get things done faster. When I did start flushing with the garden hose I heard a pop noise that I was a little concerned about.

That was over two years ago and about 30,000 miles ago and the truck runs great and I'm not losing any fluids so I don't think anything cracked. I was just wondering if most people let the engine get cold or if they typically flush when it's warm. What about at a repair shop or the dealership? I can't imagine they would wait for the truck to get cold before flushing the system.

I apologize for the long winded post.

[99' Powerstroke]

OK. If nobody has any input on this then I have another question. Can flushing a warm engine with cold water cause something to crack that won't lead to coolant leaking out somewhere?

[Mr.Ford]

I've done the flush on a warm/hot engine. Did the flush for the typical oil in coolant flush, done it over and over to get the oil out. Not the best thing to do as rapid contraction of metals could cause cracking or lose of sealing of gaskets.