While I was gone, Rob was trying to use my truck to haul other trucks, with my permission of course. Unfortunately, every time he tried to take it out, it had some kind of problem. Notably, a bad ground produced smoke during an attempt to start, and the radiator failed around the cap neck. Luckily, at this time he had a parts truck, and so he replaced the ground and also set aside a radiator for me (as well as a winch mount bumper and a new tow hitch which isn't unusually long.) Yesterday I did this radiator swap.
The radiator swap on the F250 is actually not too arduous. Everything is relatively easy to lay your hands on, and nothing much is in the way of anything. Later-model OBS fords have a bypass run to the drain plug (not the petcock) on the right side of the radiator, with a big hose (say 5/8") which goes to a teeny tiny passage, maybe 1/8". I have an automatic and the donor did not, but luckily the caps remained on the transmission cooler fittings on the transmission. My vehicle also had another transmission cooler added out front of the radiator, which I removed because it was an apparent source of leaks in the front of the vehicle. The transmission cooler lines are 5/6" ID, but the aftermarket cooler's lines were 3/8". The bypass fitting came out of the old radiator easily, and I sealed it into the new one with RTV.
Before I even got into the radiator removal, however, I installed a coolant filter. These are standard on many large diesel engines, including some installations of this engine (the 7.3l IDI from International-Navistar) in larger vehicles. The only good place to locate this filter in this truck seemed to be next to the fuel filter, so I did what many others have done and added a piece of bracket work on to the fuel filter bracket, which is massive. From this I hung an International filter head; on both the input and output there is a 3/8" NPT thread. On each side I installed a close nipple, an ell, another close nipple, a ball valve, a 3/8" MIP to 5/8" MIP adapter, and a 5/8" tee, with the straight-through fittings on the tee terminated with 5/8" MIP to 5/8" hose barb fittings, all in brass (with stainless balls in the valves.) All connections are sealed with blue RTV silicone.
The heater hoses were cut, and in one case, a piece replaced, and the tees were effectively inserted inline with the heater hoses. This is known as a "bypass" installation and it allows a small amount of coolant to pass through the filter whether the heater is being used or not. The heater provides sufficient pressure drop to permit the filter to operate, or so it is claimed. In addition, this installation should barely impede the flow of coolant to the heater core. The filter I chose provides the anti-cavitation additives specified for this motor, although the filters I ordered are charged for a twelve gallon cooling system, where mine is eight. I intend to run through these filters quickly, and then to get some with the proper amount of DCAs.
After the radiator was installed, all lines were reconnected, except for the transmission cooler lines, which were replaced with new 5/16" ID tubing from Napa. Since Kragen became O'Reilly they dropped their bulk transmission fluid-safe line, and only sell formed hoses for modern cars.
Today, I will head out to the store and pick up distilled water, having already secured low-silicate ethylene glycol coolant from Napa in Lakeport. This will permit me to actually refill and leak-test the truck. All of my new cooling system connections were made with RTV silicone and I'm not particularly worried about them, but the transmission fluid lines are a bit funky, as usual. I may require smaller clamps, which I thought I had already...