hey fellers,
i have a 93 f350 idit 5 speed dually cc with 3" dp to 4" straight pipe, i recently towed about 5k # going S on the 5 into so cal over the grapevine at around 8pm (lower ambient temp 80s?) which is 6% grade for 5-6 miles and got hot, i pulled over, it cooled and i finally i made it. this is my first idi and drove a 2012 PSD before so towing was easy in that truck. ive read on here that 3rd gear at 3k rpm ought to be sweet spot for this idi but thats when temp rose fastest. seems like it did better at about 2.5k rpm in 3rd/4th. on the way home going N on 5 over the grapevine towing about 2.5k # it also got hot but ambient temp was well over 100 that day. my goal is to be able to tow my toy hauler prolly about 8-9K # over the grapevine without having to stop bc of heat issue. the engine was rebuilt about 20k mi ago and new tranny same time with docs from PO. runs great, love this truck. i put a new water pump recently, fuel filter, air filter, coolant is new and stable, oil looks good. not sure if the fan clutch is engaging because it dont make that airplane engine sound described on here but fan does speed up with engine at higher rpm so not sure about that. i just put the vented front bumper on and towed the toy hauler mostly downhill with mild temp (220 according to pillar gauge). egts stay about 7 or lower except when i am on it then go max to 9 for just a few min. what is a realistic expectation for speed towing up that type of grade? i know the PSD i had was twice the HP and TQ as this truck so its gonna take some getting used to. any other suggestions or comments greatly appreciated. if i forgot to include any other info please let me know. thanks

 

from your description that you need to address the Fan Clutch.

 

thanks wolf!

 

Radiator may be clogged internally because of calcium or other minerals.

 

bent or damaged fins or clogged fins can restrict air flow thru the radiator, the Fan shroud is also very important.
The fan Clutch should engage between 165 and 205F so IF the air temp off the radiator is not reaching that range the clutch will not engage.
And yes it sounds like a Jet when it is locked up. I can hear mine in the cab when it kicks in while cruising, and I'm half deaf

 

For what its worth, my 92 gets hot as soon as the pyro climbs past 700. New engine, re cored radiator, working fan clutch etc etc, but mine is making right around what your 2012 makes. Ive got an intercooler in front on mine, only real difference. If its 90-100 i cant even pull 5-6 miles of 6% empty without it hitting 230. So i guess what im basically saying, im subbing this thread just to see if something is mentioned i havent thought of.

 

thank you! glad to hear im not alone in this, appreciate all the feedback guys

 

This^^^^^

If you do some digging you'll find not all fan clutches are the same. I remember reading threads from the mid 2000's where people were having problems with auto store fan clutches and the conclusion seemed to be that if you're towing or live in a really hot climate you need a good heavy duty fan clutch. Iirc the prices were listed as between 300-400

With the extra power you're making that heat has to go somewhere. I won't if you could rig up a locked fan clutch just to test as see. From what I understand wore/cheap clutches slip too much when at full lock.

Another option would be to get a machine shop to spin you an adapter and run something electric like a 6.0 powerstroke fan clutch, I'm pretty sure the fan itself has the same bolt pattern. I'm not sure but I imagine it's probably pulse width for a duty cycle and some guys tie into the blue wire (look up blue wire mod) with a switch to get full lock.

Those are pricey clutches too, you don't want anything other than a motorcraft and junkyards have been really hit or miss for me on replacements. Some work, some don't, most that work, don't work long.

 

Its the NAPA HD option for an IDIT was around $260 iirc. Ive thought about locking the fan just to see for sure, but im 97% certain this is pulling all the airs. Been looking for a good deal on a horton but no luck so far.

 

Now I'm sure this would be unbalanced and hell on water pump bearings but an old man once told me he'd drill a hole in em, drain the oil out and pump em full of silicone. I have no clue if that method actually works or not but it would be an easy test if you have a junk clutch laying around.

Some guy on here built some angle ironish brackets on his to lock it iirc, the clutch on my 85 I had to add tension to the spring my moving it a bit outwards. I used a dab of either jb weld or quicksteel to hold it. Different brands have different notches but this one was easily moved.

I really hope you figure out something, overheating issues are aggravating, just out of curiosity does it make a difference if you drop a gear and keep the revs up?

 

All you have to do is tighten the clock spring on the front...

 

Wouldn't you then still be relying on the clutch to hold the load and not slip though?

I doubt there's much of a difference most people would notice between a fan at 80% and one at 100%

 

I mean its viscous sure, so theres probably some slip, but ive done it. You can take the oldest most clapped out fan and it will lock. Had to do in my 79 to keep from overheating in traffic.

 

thanks for all the info fellas, i tried to find the napa one and it was about $250 although they were offering 20% off since i have AAA but they were completely out of stock. i got the hayden 2830 which some guys on here have used with success. gotta get that 48mm wrench now too and i already got a motorcraft themostat to put in so with that i think it should all be better. im going to make an air dam out of sheet metal at the bottom of the front fender (didnt have the diesel bumper on previous trip) to force more air up into lower part of radiator. PO said rad was new and it looks it. had to replace the water pump which would have been just 2 years old according to PO (and motor rebuild docs) so that lends value to the fan clutch being bad as stated by dark over cast.

on a side note, i put down a bunch of sound deadening/heat barrier stuff (summit version of dynamat) and that really helped decrease noise level which is nice.

i also swapped my rear seat to the front as it was like new, simple little job swapping the back side of seat but more comfy. felt like a genius.

 

Fun fact, the rear seat in a crew cab is the same as the seat in a regular cab.

Also on the regular cabs I pull the seat rod so it will lay all the way back against the cab and you get a little more room.