Hi, guys!
I have a 92 F250 with a 7.3L IDI that had less than 20K miles on an overhaul when I installed it. I've put about 7500 miles since the swap and it runs great! When I did the swap, I also installed a new aluminum radiator, hoses and a thermostat. Still using the clutch fan, well, because it works. I have a mechanical coolant temp gauge because I know the dash gauge is a glorified idiot light. Normally, the truck runs 195F. 210F on a hot day. (100F) I was pulling a dump trailer with a skid loader inside of it on a 103F day and the coolant temp got to 240F. Backed off to around 55-60mph and it came back down to 235F. I only ran for about 20 miles this way then dropped the trailer and went on my way. My question is, am I hurting anything by running that hot? As soon as we slowed down and parked the trailer, it cooled right off.

 

Its a little on the hot side but not enough to hurt anything, as long as you have at least a 50/50 coolant mixture and a good radiator cap. The coolant shouldn't boil inside the motor, its when they boil over and loose coolant that you cause damage. Remember the coolant sensor is on the top of the cylinder head, the hottest location, the coolant entering the water pump after going through the rad will be several degrees cooler.

 

I would go above 240*, but anything below it should be okay......or atleast that is what i have seen multiple times. I believe 240* is where the over temp light is supposed to turn on.

Did your fan kick on? While the actual kick on temp can vary some, it ahould have come on before you hit 240*. Probably somewhere between 225* and 235*. If it didn't kick on then either the clutch is bad or you need to clean/adjust the tempature spring on it. If you search you can find the procedure to adjust it.

Also, make sure all your coolers/radiator/AC fins are clean. If they get clogged up it can kill your cooling as well.

 

Thanks for the information, guys! I couldn't tell if my fan locked in for sure, but I will check out and clean the temp spring. The radiator and a/c condenser are both new so I know their fins are clean.
I put a lot of work into the engine swap. I just don't want to mess it up.
This website has helped me out of so many jams. Thanks again!