it surprises me this was nessasary for an upgrade as the 6L cooling was way better then then 7.3L, infact it was a 7.3L upgrade to install a 6.0L radiator, so I always thought they were good.
I think the severe duty fan clutch is the better way to go for controlling heat. I did that and I do not hear the supposed greater noise people say happens unless the computer tells the fan to lockup. You do hear it then. You can also see the engine temperature rapidly begin to drop. When I hit that fan switch, the overheating goes away. I'm trying to get to where the fan is only needed in the worst of situations. I purposely avoided using the fan switch during testing this trip. I probably would have had no issues had I switched the fan on. I wouldn't have the results I was looking to get though. The other advantage of the severe duty fan clutch over the 7.3 adaption is it plugs into the wire harness and works with the system so you don't get an engine MIL light. If the 6.0 Liter radiator is considered an upgrade for the 7.3, that would suggest the 6.0 Liter does run hotter and needs greater cooling. The 7.3 reservoir bottle vent hose could connect to the the tube on top of the 6.0 radiator but an alteration would have to be made for the hose from the bottle that connects to the bottom of the radiator since the 6.0 only has one connection.I recall reading a 6.4 liter radiator was an upgrade to the 6.0 Liter. I'll have to check on that.
ya, you didn't say the fan was unplugged in your test, that was a good chunk of info you left out haha.
why are you trying to avoid that coming on, it will only come on at factory set values and thoes are based off temp. so if you have inproved the cooling it should by default come on less. I would put it back in service (controled by the truck computer) and do the test again and see what happenes.
