How do I flush the radiator on 96 F-250 PSD? I do not see a cap on top of the radiator. Is this what they call a sealed radiator system?

 

First of all, let me say that I have the V-10 gas engine so things may be a little different on the diesel.

I put one of those Prestone flush "T's" in to backflush the system. The T attaches to one of the heater hoses. I backflushed until clear water came out of the top radiator hose, which you have to disconnect from the radiator. I then used air pressure (about 5-10 psi) to blow the water out of the system. I do this to minimize the amount of tap water in the system. I like to use distilled water along with the antifreeze.

I then decided to remove the engine block drain plug to see if any more water would drain out. I was shocked by the large amount of very dirty water/coolant that drained out. Somehow the backflush and air purge missed this pocket of water/coolant.

I also found that the system filled up several quarts short of the stated capacity. I don't know if the capacity is incorrect or there is more "trapped" water in the system.

Similar steps should apply to the diesel engine.

Pete