1990 7.3 IDI (turboless) fan clutch replacement

[mikadobrain]

Hey guys,

i need help finding a replacement viscous fan clutch for my 1990 International 7.3L IDI. The engine does not get to operating temperature, the fan is engaged 100%. I removed the clutch and tested it with a heatgun - the spring moves noticeably, but there is no difference in "firmness" of the clutch on the shaft.

I found this replacement part:
https://kit-masters.com/product-detail/?pid=1519
but it is pretty expensive and i would have to buy a new fan also (the holes in the old one don’t fit the replacement clutch - maybe i could place new holes).
At rockauto.com a clutch for the Ford IDI is ~100$, but the Ford clutch is mounted using a large nut, while mine is bolted to the pump through a plate (as can be seen in the link i posted)

Do i really have to buy that expensive replacement + new fan? Shipping and customs would kill me. I’m located in Germany

Are there places to look for used clutches, or maybe remanufactured ones? Maybe a fitting mounting plate can be screwed onto the nut of the Ford replacement clutches?

Any hint is greatly appreciated!

Regards,
Michael

[Jolly Roger bus 223]

have you checked with your local auto parts store?
either piece or both are at least available if not next day there.
figure out which year range your engine is? it does varie but not by much with your issue?

[Jolly Roger bus 223]

sorry i didnt see where you were located
a vicious fan clutch locked up is not a bad thing?
might make some noise but its doing its job.
replace the clutch? and keep the fan.
but fan blades do wear out and can kill a radiator when they lose a blade or belt?
a new flex fan if you are just starting your journey

[cadillackid]

Originally Posted by Jolly Roger bus 223

sorry i didnt see where you were located
a vicious fan clutch locked up is not a bad thing?
might make some noise but its doing its job.
replace the clutch? and keep the fan.
but fan blades do wear out and can kill a radiator when they lose a blade or belt?
a new flex fan if you are just starting your journey

100% engaged fan will cause low temp esp in winter.. the thermostat will constantly cycle open and closed ...


kills the little fuel economy you have running fan for no reason


flex fans are designed to be used without a clutch and they are noisy as crap and also run all the time wasting energy.. not a fan of them one bit.


a proiperly operating clutch fan is the way to go.. a Cheapie fan clutch will give Cheapie results.. I either convert to electric engagement clutches or run kit-masters borg warner clutches.. nothing but.. and have great results.. clutch in my DEV bus is nearly 5 years old and lots of use and still operates perfectly..

[Simplicity]

Not sure about this, yet could you use an all electric fan?

I know another poster had his clutch fan go and and installed electric fans, at least until he can find a less expensive ($1200) replacement.

[mikadobrain]

Originally Posted by cadillackid

I either convert to electric engagement clutches or run kit-masters borg warner clutches..

Right, i definitely want a working clutch.

Those electric clutches - the fan is driven by the water pump shaft, but the clutch is operated elelctrically? How is it triggered, is there a sensor on the front of the clutch, or do you have to install sensor somewhere on the block? i

I definitely would go that way, but have no clue what clutch i need. If you could point me in the right direction...? Part number would be perfect, but good resources to do my own research are nearly as good.

Anyways, thanks a lot.

[rossvtaylor]

Originally Posted by Simplicity

Not sure about this, yet could you use an all electric fan?

I know another poster had his clutch fan go and and installed electric fans, at least until he can find a less expensive ($1200) replacement.

That would be me... Yes, the 2-speed fan clutch on our Freightliner seized up and rotated, ripping out the two wires. The replacement is $1200 so, for the time being, I installed two electric fans which I had from another project. They actually seem to be working adequately for now.

[Booyah45828]

You hear the fan roaring the entire time?

Even with the clutch frozen engaged, the coolant should at least get to the temp the thermostat opens at. If you're not getting up to that, then you're thermostat is likely faulty. What temp do you get up to? Are you relying on the factory gauge and did you verify that it's correct?

You might find a used clutch, but that's not the route I would recommend going. A fan clutch isn't something you want to risk using used parts on, because failure could get expensive quick.

[mikadobrain]

Originally Posted by Booyah45828

You hear the fan roaring the entire time?

Even with the clutch frozen engaged, the coolant should at least get to the temp the thermostat opens at. If you're not getting up to that, then you're thermostat is likely faulty. What temp do you get up to? Are you relying on the factory gauge and did you verify that it's correct?

You might find a used clutch, but that's not the route I would recommend going. A fan clutch isn't something you want to risk using used parts on, because failure could get expensive quick.

The Thermostat is most likely faulty. I have the factory gauge and it bareky moves during normal winter operation. Replacement is already on its way.
If i can get my hands on a Laserthermometer i will check. I suppose the factory gauge is nearly accurate. When going uphill in summer it does move. The overheat warning light flashes somewhere above 200. I dont recall it exactly.

Looks like i have to pax.. electronic clutches are equally expensive. Just have to measure my fan. Hopefully i get it right.


Edit : no roaring. never heard it roar. when the engine is off and i turn it by hand it immediately stops. suppose it is frozen somewhere between open and closed.

[cadillackid]

from what ive found is the thermostat cycles in cool weather so your dash gauge almost never reads up to temperature as the thermostat opens and then that extra cold water goes through the engine reaching the thermostat and slams it back shut.. this is esp true with low engine loads.. with higher engine loads sometimes the radiator can build enough heat that the water is at least close to hot and allows the T-stat to regulate some and you'll see a more steady gauge near operating temp..

[Booyah45828]

Originally Posted by mikadobrain

The Thermostat is most likely faulty. I have the factory gauge and it bareky moves during normal winter operation. Replacement is already on its way.
If i can get my hands on a Laserthermometer i will check. I suppose the factory gauge is nearly accurate. When going uphill in summer it does move. The overheat warning light flashes somewhere above 200. I dont recall it exactly.

Looks like i have to pax.. electronic clutches are equally expensive. Just have to measure my fan. Hopefully i get it right.


Edit : no roaring. never heard it roar. when the engine is off and i turn it by hand it immediately stops. suppose it is frozen somewhere between open and closed.

If it's frozen engaged, it will roar. The increased air movement is very noticeable, so if you're not noticing anything, I wouldn't consider it frozen engaged. The clutches more often fail by not/never engaging and causing an overheat issue.

[Booyah45828]

Originally Posted by cadillackid

from what ive found is the thermostat cycles in cool weather so your dash gauge almost never reads up to temperature as the thermostat opens and then that extra cold water goes through the engine reaching the thermostat and slams it back shut.. this is esp true with low engine loads.. with higher engine loads sometimes the radiator can build enough heat that the water is at least close to hot and allows the T-stat to regulate some and you'll see a more steady gauge near operating temp..

Operating temps really depend on the exterior temp. If it's below freezing out, the engine might not be making enough heat, especially at an idle. Even near freezing you might not be making enough heat if the interior heaters are blowing full blast. Running down the road though should be making enough heat to get to the thermostat opening temp, especially with shutters/winter front. That's why there are winter fronts/radiator shutters, to keep the ram air through the radiator from cooling the engine too much.

As far as the thermostat cycling, I've only ever seen that happen on certain engines the first time or two that it opens. Coolant temp will rise well past the opening temp, 210 degrees or so. It will then open fully, rushing in a bunch of cold coolant, and then drop to around 160, before raising back to 210 again. It will cycle like that a time or two, then act normally. They say that phenomenon is actually caused by a pressure differential below and above the thermostat created by the water pump. But after an opening or two, the pressure should be equalized and the thermostat would begin to regulate like it should.

If you're not up to opening temp after running for a while, feel the upper radiator hose. If it has any warmth at all, your thermostat is either opening too soon, or is not sealing completely and allowing coolant to bypass. The thermostat leak might be large/cool enough that the engine won't heat up to opening temp with it occurring.

Modern cars and trucks actually have programming in their ecms to detect a cool running engine or a slow warm up. And that fault is typically caused by a failed thermostat. They monitor this for emissions purposes, as a cold running engine creates more pollution.

[Booyah45828]

If you think your issue is caused by a failed engaged fan clutch, remove the fan and test it again, that will show if the fan is cooling too much. But I really doubt that it is.

[mikadobrain]

Thanks. The new Thermostat is already on its way, so i will change it nonetheless. The old one has ~200.000 miles on it.

The clutch doesn't react. If it is frozen open or closed doesn't matter in the end, i will have to change it. So i'll get a viscous replacement and a new fan. Just don't tell my wife
Where do you guys get your clutches and fans? Is kit-masters a good address?

Just curious: how does an engaged clutch feel when you try to turn the fan by hand? How much resistance? There is noticeable air movement next to the engine and it's loud. But i wouldn't describe it as "jet engine". Unfortunately it already was that way when i got it, so no way for me to tell if its abnormal or not.

[cadillackid]

Originally Posted by Booyah45828

Operating temps really depend on the exterior temp. If it's below freezing out, the engine might not be making enough heat, especially at an idle. Even near freezing you might not be making enough heat if the interior heaters are blowing full blast. Running down the road though should be making enough heat to get to the thermostat opening temp, especially with shutters/winter front. That's why there are winter fronts/radiator shutters, to keep the ram air through the radiator from cooling the engine too much.

As far as the thermostat cycling, I've only ever seen that happen on certain engines the first time or two that it opens. Coolant temp will rise well past the opening temp, 210 degrees or so. It will then open fully, rushing in a bunch of cold coolant, and then drop to around 160, before raising back to 210 again. It will cycle like that a time or two, then act normally. They say that phenomenon is actually caused by a pressure differential below and above the thermostat created by the water pump. But after an opening or two, the pressure should be equalized and the thermostat would begin to regulate like it should.

If you're not up to opening temp after running for a while, feel the upper radiator hose. If it has any warmth at all, your thermostat is either opening too soon, or is not sealing completely and allowing coolant to bypass. The thermostat leak might be large/cool enough that the engine won't heat up to opening temp with it occurring.

Modern cars and trucks actually have programming in their ecms to detect a cool running engine or a slow warm up. And that fault is typically caused by a failed thermostat. They monitor this for emissions purposes, as a cold running engine creates more pollution.

the engines in question are my DTA360 and my T444E.. my DTA360 does have a winter air shutters anbd does in fact eliminate any thermostat cycling as the radiator water stays warm enough that the return fluid is not outside temp.. the issue comes into play when a fan is running full bl;ast without a winter front. . the radiator super-cools the water so that when the stat opens the top hose gets warm and the water flowiong through the radiator is cooled significantly.. in fact back close to ambient temp.. once that water travels back into the engine it cools the engine very quickly.. esp if the driver lets off the accelerator or decelerates where the engine produces little heat.. the stat will close up fully or almost so.. the engine warms quickly and often opens the stat a bit too far again... I'll observe this cycling .. real world experience.. yes I do know about the heaters pulling off more heat than the engine makes.. this is the case in my DEV bus.. even with my air shutters if I idle down for any time at all I'll see the temp go down.. a couple of my winter trips this past february were -5 to -10 below zero f and while driving in town I had to run the webasto and the engine to keep it anywhere close to operating temp.. my top radiator hose was barely warm right near the neck and pretty much cold by the time it reached the radiator.. there is always a little bleed from the air bleed hoile im the thermostat so a small amount of warmth in the top hise is normal..



on the highway with my air shutters closed and my fan clutch operating in minimum speed as its supposed to my engine temp stayed above T-stat opening (stat is 180, temp was around 190 or so)...



with the electric cutch on my red bus its pretty easy to make my T-stat cycle if I cut the fan clutch into manual On mode where it runs 100% of the time on high speed.. I dont observe that with the fan in Normal (OFF in winter) mode.. that fan has no minimum speed.. it freewheels somewhere around 100 RPM or so.. that bus was in-service in texas so no winter front or shutters on it... that 7.3 makes a lot more heat than the DTA360 as I have no issues keeping the heaters warm even in town for the most part.

[BeNimble]

I replaced the clutch fan setup on the vintage motorhome with an electric fan.
One from a 2000ish volvo wagon, it is a monster powerful fan.