Had an all metal dual core in the rafters and wanted to clean it out before I used it. Grabbed fluid pump at work, (used for draining hot water tanks), two clamps and some Prestone flush and fill.

 

Rinsed it with the petcock open and the faucet as hot as possible, closed the petcock and added 1/2 the bottle of cleaner and closed the radiator cap. Let circulate for 20 minutes and rinsed thoroughly after disconnecting all the hoses.

Cool did it get any gunk out ?

some, the water was initially dark when I dumped it and rinsed to clear, the car it came from was not maintained and I wanted to make sure it was clear of crud

-like stop leak left over from the donor car's heater core leak-

 

I didn't have any problems with the rad itself before, but since I was putting it on an ea82T I wanted to be confident it was as decent as possible before I mounted it

 

doing it in the shop like that was easier in a way than cutting a heater core line for a flush and fill kit, running a hose and discharging a toxic mess to my yard

 

thought it might be useful to other folks in the north for winter work when a big mess from a flush kit isn't an option

I usually degrease the coils and blast-rinse them with hot water, too. Any road grime in there just blocks air and traps heat, yanno?

Yeah, I washed a lot of road grime out of the fins too, tons and tons, it amazed me how much crap rinsed out.