Fan clutch frustrations

[Michael Fowler]

I think this is the answer. Some may remember the Rally a few years ago where we discovered that my radiator was plugged. It wasn't allowing the clutch to feel the heat because it wasn't transferring the heat to the air. Unfortunately there is no easy way to know if the tubes are clogged or not. In my case it took an insufficiently tightened fan assembly that unscrewed itself a few seconds after I shut off the engine. The blade sliced the core, causing a leak, but also allowing examination of the interior condition of the tubes.

See if the lower part of the radiator gets hot when you run the engine.

 

[pennsylvaniabo]

I have issues with my fan as well. I know for a fact that i have a new clutch fan, t stat and rad and I can still get to 230-240 range and cannot hear the fan kick in.

 

[MIDNIGHT RIDER]

Clutched fans are a joke.

No wonder the temperature gauge gets on people's nerves if the things aren't even supposed to engage until dangerous territory.

A more realistic engagement temperature range would be 160* to 180*, thus the radiator would be somewhat a benefit when the thermostat opened.

There is a chart somewhere that shows the percentage of engagement when the various ratings of fan-clutch "lock up".

The severe-duty ones only spin 70% of belt-pulley rotation when fully engaged.

None of them actually "lock up".

I am a firm believer in direct-drive fan hubs; lacking that, PIN the clutch solid.

An even better option is a big pair of electrics.

I have ran several of my engines in both clutched and direct-drive configurations and can tell no difference in power or mileage.

I can, however, tell a big difference in A/C performance and engine cooling with the direct-drive being by far the best performer.

 

[justinray]

I've had the truck in my sig for 2 years, and twice, TWICE has my fan clutch ever kicked in while I was driving. Hmmm. && That's in Texas.

 

[boxathey]

what year windstar is that pair of electric fans out of id love to do the swap

 

[pennsylvaniabo]

How east is it to pin these fans? I want to start there and go electric at some point.

 

[jaluhn83]

Interesting everyone has so much trouble. Mine has always come on about 205*, sometime around 200*. Never had fan clutch issues at all. Not sure what brand, OEM, aftermarket or what, it was on the old black truck when i bought it and got swapped over the the turbo since it works so well.

I'm also running a rebuilt 4 core radiator.

Just my $0.02, but I like the stock clutch setup. Never had any problems.

 

[RLDSL]

Russ... Ever given much thought to removeing the heads and takeing out the closed off coolant ports in the block and heads... I know its plenty of hard ass work but why are these 4 passages closed off in our engines but open in the 6.9 engines... Its never mad good sence to close off coolant passages in an engine... Unless it was for better fuel mileage because the engine ran warmer or because the epa said the engine ran too dirty. So the craptacular engineers found out closeing off those ports heated up the engine enough that the fuel burned more... I don't know but its weird as hell to me. Pulling the heads.. Installing the 6.9 head gaskets on a 7.3 will work fine. I have measured the 6.9 and 7.3 head gaskets and they are demensionally the same every place but the lower head to block corner coolant ports.

Old thread here but just in case y'all missed it, i pretty well figured out why they blocked those ports off. With an oversized rad like would be found in a mid sized chassis ( or my rodney red) and fans thad kicked on too soon like when i put me e fans in and had the switch set to kick on at 190, the water at the bottom of the rad returning to the engine was so cold and its path across the front of the heads even with the restriction was not slow enough to keep it from fluttering the thermostat closed . thing would run fine until those high pull fans kicked on and pulled it down cold fast, once that happened, the stat wouls flutter shut and the engine would overheat with hot watr not reaching the stat . a really wierd situation, but obviously they had run across something similar with the 6.9 in the larger trucks and chose to block off those ports to fend it off. in a totally stock configuration, everything is balanced out just right.

 

[FORDF250HDXLT]

what year windstar is that pair of electric fans out of id love to do the swap

i used: 1995 - 1998 for the tall narrow rad.would fit much easier upside down and not hurt a thing.i shaved some shroud to sit in closer to rad instead.
but other years may also fit.
most of the time,they just sit there off.on our hotter days here in Maine (80's with a handful of 90's and rare high 90 days) they'll work some when loaded up no doubt,even then it's not for very long and mainly just the hills,or sitting in traffic etc.
i keep under the max combined gross ratings.mainly up to 14-16k gross.
copper rad
50/50 fleetcharge
motorcraft t-stat
good variable rate fan controller.-this makes all the difference.

 

[pennsylvaniabo]

i used: 1995 - 1998 for the tall narrow rad.would fit much easier upside down and not hurt a thing.i shaved some shroud to sit in closer to rad instead.
but other years may also fit.
most of the time,they just sit there off.on our hotter days here in Maine (80's with a handful of 90's and rare high 90 days) they'll work some when loaded up no doubt,even then it's not for very long and mainly just the hills,or sitting in traffic etc.
i keep under the max combined gross ratings.mainly up to 14-16k gross.
copper rad
50/50 fleetcharge
motorcraft t-stat
good variable rate fan controller.-this makes all the difference.

Do you find the windstar fans do ok? I know I switched to electric on my offroad truck and it makes all the difference in cooling. Really tempted to try in on the tow rig.

 

[Black dawg]

Do you find the windstar fans do ok? I know I switched to electric on my offroad truck and it makes all the difference in cooling. Really tempted to try in on the tow rig.

Just lock it up solid, you wont lose power and it will run cooler. Is your truck serp belt or v belt. I know someone who is working on building a water pump pulley for serp belt trucks that will increase wp speed 10% and fan will bolt directly to it (no more clutch).

 

[jaluhn83]

Negative. The back 2 ports are blocked off in the 7.3 due to issues with coolant weapage from the back corners of the heads on the 6.9. Reference is a IH mechanic's info handout discussing changes from the 6.9 to 7.3 though I cannot find a copy of it.

Old thread here but just in case y'all missed it, i pretty well figured out why they blocked those ports off. With an oversized rad like would be found in a mid sized chassis ( or my rodney red) and fans thad kicked on too soon like when i put me e fans in and had the switch set to kick on at 190, the water at the bottom of the rad returning to the engine was so cold and its path across the front of the heads even with the restriction was not slow enough to keep it from fluttering the thermostat closed . thing would run fine until those high pull fans kicked on and pulled it down cold fast, once that happened, the stat wouls flutter shut and the engine would overheat with hot watr not reaching the stat . a really wierd situation, but obviously they had run across something similar with the 6.9 in the larger trucks and chose to block off those ports to fend it off. in a totally stock configuration, everything is balanced out just right.

 

[jaluhn83]

With respect, I disagree. Clutched fan are an excellent and perfectly functional solution to cooling. They are designed to move sufficient air for cooling for normal load with a proper cooling system. They're designed to come on around 210*, not sure where all this 240* junk is coming from.

I think most of the problems are either junk clutches or other problems showing up. Now, the stock cooling system is designed for a non turbo, so if you put a turbo on an turn up the fuel you're going to stress it more. Likewise, rated GCWR on these trucks is something like 13000-16000lb depending on axles and trans. If you're pulling more than that you're already outside of the design load.

The ideal engagement temp is 200-205 IMHO. You don't need it on any lower, 90% of the time there's sufficient airflow just from driving so having the fan on any lower would just be a waste.

The fan is designed to take into account that clutch slip.

Now, I wouldn't mind having a true clutch system like they use on big rigs, but then there's reliability issues with that as well. The fan clutch is simple and reliable. No electronics to fail/corrode/fall off/whatever.

I've never heard of an electric fan setup that would move enough air to really work on one of these rig. Plus then you're adding a bunch of wiring and controls that can potentially fail.

Clutched fans are a joke.

No wonder the temperature gauge gets on people's nerves if the things aren't even supposed to engage until dangerous territory.

A more realistic engagement temperature range would be 160* to 180*, thus the radiator would be somewhat a benefit when the thermostat opened.

There is a chart somewhere that shows the percentage of engagement when the various ratings of fan-clutch "lock up".

The severe-duty ones only spin 70% of belt-pulley rotation when fully engaged.

None of them actually "lock up".

I am a firm believer in direct-drive fan hubs; lacking that, PIN the clutch solid.

An even better option is a big pair of electrics.

I have ran several of my engines in both clutched and direct-drive configurations and can tell no difference in power or mileage.

I can, however, tell a big difference in A/C performance and engine cooling with the direct-drive being by far the best performer.

 

[pennsylvaniabo]

Just lock it up solid, you wont lose power and it will run cooler. Is your truck serp belt or v belt. I know someone who is working on building a water pump pulley for serp belt trucks that will increase wp speed 10% and fan will bolt directly to it (no more clutch).

How do you lock them up? anyone have a write up?

 

[SparkandFire]

I locked mine up by undoing the spring from the epoxy (where it is anchored to the aluminum NOT the center shaft...)
then I turned the spring about 10 degrees counter clockwise. Then I cut the spring off where it matches up to the anchorage point, bent it in a U shape, and stuffed it back into the anchorage point.

If you have a heat gun or hair dryer you can check to see which way the spring rotates... Thats how I did it.