I knows there's the big debate on whether to use concentrate or premix that goes on everyday. I'm not concerned about that, just to clarify up front!! I've already bought the pre-mix so I made my decision.

I've seen and heard many different techniques to flushing the system, but all involve having the motor in the truck. Those involve pulling the t-stat and running water via a garden hose through everything while the trucks running until there's no color to the liquid draining out. Other's have said to leave the t-stat in and do the same thing. Many buy a crapload of distilled water to do this also. On DieselSite, they recommend pulling the heater hose from the timing cover and the plugs on both sides. then flush the heater core and the block. Then using compressed air, blow the remaining water out. Doesn't involve running the engine.

So here's my deal: I've got the motor on the stand that's going in the truck. This weekend I'm pulling the other motor out so I'll have access to the heater core and radiator buy themselves. I'm filling with the Cat ELC premix.

Can I just do the DS flushing/air on the block to evacuate all the old coolant and water that will remain? Will the water pump still have the old coolant in it if I do this? If using compressed air to blow the block out, will all the water be blown out??

Next, will this same technique work on the heater core? Is there anywhere in there that fluid can stay trapped if I blow the water out?

As for the radiator, I am just going to run water thru it to flush and drain out.

I've been taking pics along the way and will continue to do so, so I'll start another thread when I'm farther along.
Thanks guys!!!

 

I did this on my F-150 when I flushed it before, I havent done it on the psd yet. But when I did it on the half ton, I did just like the DS said, except with the engine running and the Tstat out. I ran it like that for a good bit. Then with distilled water.

You can pull both heater hoses off and flush the heater core with a garden hose, then compressed air, but there will still be some water in there.

 

That's what I was going to do with the heater core. But not until the motor is out cause it's easier to get to. How about the block? Would it work on it as well?

 

This is how you would flush and change the fluid normally... see:
Coolant changing instructions... - Diesel Forum - The Diesel Stop.com