I was wondering wat the highest temp anyone has seen on a 7.3 IDI was when cruising down the highway?? Mine runs at about 200-205'F. I have dual Flex-a-Lite Electric fans tat pull 5500 CFMs of air and it still runs at tat temp down the highway, and im empty.

 

The thermostat don't open till the engine gets to 195.

235 to 240 when working it hard.

Good luck with the Flex Lite fans, waste of money as primary fans in my book.
They don't last long enough to recoup the purchase price with fuel savings.
Been there did that before.

 

Ok thanks. I figured i would try the fans and c how it goes. My original fan hub cooked so i looked for one and no one could get one. But someone said that they cost like $800.

 

Bull on the $800 - there is a shop that makes performance fan clutches for like $600 or so, but a stock one runs as low as $150 for the Hayden severe duty unit. That said, I do not like fan clutches, and I don't drive fast enough for the air drag to come into play - I locked my fan to the water pump for now, some day when I feel rich I'll do a Mark VIII fan swap.

Oh, and I second Dave's opinion on the Flex-A-Lite - I'd trust them when I see an OEM installing them in a production vehicle, till then I'd always go for an OEM assembly of suitable size and flow rates.

 

And the advantages of that are?

 

Keeps the fan turning all the time, I can sit in traffic with the A/C on and not see any increase in engine temperature - stock fan clutches have some stupid-high temperature of 100% engagement, like 265F or so, by which time guess what's your engine's condition Additionally, they are thermal clutches, but considering how far away from the radiator the bi-metal spring sits you really need external airflow to take heat from the radiator and transfer it to the clutch - well, when you're in a gridlock, the only airflow through the radiator is the one caused by the fan itself, which ain't much partially cause the clutch ain't engaged 100%, and partially cause it is by now kinda worn out. So you end up sitting in traffic, idling at 600 or so, and watching your temperature climb slow but steady. That's in MI at 85F and high humidity, I'd imagine in places like FL if your fan clutch slips even a little you're pretty much screwed. With the fan locked to the water pump I have 100% airflow as long as my engine is running, so I can easily deal with the lovely afternoon rush hour traffic on 696 or 75. Downside of this would be the air drag the fan would impose at freeway speeds, but considering I only drive as fast as 52mph (1700-1750 rpm, I like my 22mpg thankyouverymuch) that really ain't something I'm too worried about.

 

well i can relate with snowman. i grew up in manitoba, not all that far from grunthal really, just moved to ontario last fall. anyway up until the dollar went to par, we would get hammered on all parts, factory, aftermarket. you name it. i did price out a fan clutch last summer and they wanted 389 or something liike that for aftermarket NAPA CRAP and the better part of 500 from ford. Now i just order everything US side and have it shipped to a depot 3 miles across the border. well thats what i did then. now....well have not ordered anything since i moved.

 

Ditto the low road speed ... I seldom go over 55 ... Maybe to pass a motorhome doing 40 in a 55 ... My usual speed is either 25 or 35 ... Almost wonder if I should do a pre-emptive bolting of the fan before it goes out ...

 

They don't really go all of sudden, they simply start engaging less and less - basically if you sit in traffic for more than 5 minutes, and you see your temperature starting to climb, even if it don't really go out of the "NORMAL" range I think you should do something about it, at least an investigation.

Oh, I should probably mention I'm running a 7lb cap, not the 13lb stocker, result of that compared to the stock setup and before locking the fan clutch was that engine would run a bit cooler on the freeway, but would also heat up faster when hitting gridlock, or for that matter even idling in Park.

 

I do a bit of idleing on the beach approach waiting to see who gets stuck in the sand ...

 

locking the fan clutch isnt a great idea , first of all when you turn off a diesel it stops immediately and i have seen fans break loose and spin off of the water pump directly into the radiator
secondly it is a waste of engine power and fuel economy
texas heat is only second to a few other areas in the summer
it is quite normal to see a temp rise when sitting still
the thermal unit gets heat from both air flow and transferred heat from the water pump shaft so it will see heat no matter what
the fan never quits turning even with a bad fan clutch
and it locks up much lower than 265 degrees as stated earlier

 

Oh yah, I know the disaster scenario, that's why I didn't pin the clutch, but used brackets to hold it to the water pump pulley - worst case if the brackets snap in half the fan will just freewheel like it normally does, as the clutch assembly itself has not been altered in any way. And my diesel don't really stop immediately, it always slows down for a sec, and then stops.

About the engine power and fuel economy losses - I know that's what should happen, however I've ran both my Lincoln and my C10 Chevy with all sorts of combinations between stock clutch fans, flex fans, and spacers and solid hubs, and I never noticed any decrease in power or mileage. Actually, with this truck, it seems to be the opposite - since I locked the fan and bumped the transmission line pressure, both of which should decrease fuel economy, I've been seeing city driving mileage of around 14mpg, whereas before that my regular was 10 or so, maybe 12 on a good day. Why and how that is, I dunno, it makes no sense to me, but as long as it works I ain't complaining.

Interesting info on the heat transfer tho, hadn't thought about the pump shaft as a media for it. Also, if it ain't 265F, then what's the stock fan's temperature of full engagement? And I know the fan always turns, tis just that the clutch was so loose that I had to keep my eyes peeled on the gauge every time I got stuck in traffic, now I just feel safer about it.

 

Tat was the price i could get in my area. after i heard tat from about 4 shops i said screw tat and decided to install my electrics. NO PROBLEMS! i do lots of off-roading and have no issues. its also my daily driver.

 

I actually found tat i got a little power and a little better milage. But WOW You only got 10 or 12 and now its went up to 14mpg. Tats kind of a shock. Ive seen 16 and get about 13-15 constant.

 

Oh, that's just my average city fuel economy, but you gotta take into account the fact that I live very close to work and school so for the most part engine is always running cold - I arrive at my destination and shut it off just before the thermostat starts opening. I towed a 30ft enclosed race car trailer last night, I got about 15mpg, and that includes climbing some hills on cruise control. Regular driving with no load I see about 20mpg, on my way back after the trailer delivery I got like 14 with front tank leaking and pedal to the metal for most of the way.