A plugged radiator or A/C coil can certainly cause cooling problems. But do not overlook the fact that the clutches on these trucks are a well known problem. Ford designed them to come on at the last minute, and the aftermarket ones can be junk, like most aftermarket stuff you buy now.
Let’s talk fan clutch
- Thread starter vegas39
- Start date
A plugged radiator or A/C coil can certainly cause cooling problems. But do not overlook the fact that the clutches on these trucks are a well known problem. Ford designed them to come on at the last minute, and the aftermarket ones can be junk, like most aftermarket stuff you buy now.
Garbage_Mechan
Garbage Mechanic
I will be among the first to admit aftermarket parts are often inferior these days. However I cannot count the number of times that the actual problem was being overlooked because “everyone knows those are...........” (fill in the blank with the latest issue) My point is do the testing. Run the checks. In the case of these fan clutches consider the possibility something is effecting the ability of the thermal coil to sense the air temp, perhaps internal or external blockage.
When I see people replace parts repeatedly I wonder how many new parts are actually defective.
When I see people replace parts repeatedly I wonder how many new parts are actually defective.
Macrobb
Full Access Member
Also, if you can find one off a IDIT(or IDIT spec), they lock in at a lower temp than the NA ones were designed to.
I've gotten ahold of a couple of those and was amazed when it happened - it was locking in around 212F, vs 225-230F for me.
I've gotten ahold of a couple of those and was amazed when it happened - it was locking in around 212F, vs 225-230F for me.
Do they actually use a different part, ie: different part number?
I’ve been giving this a lot of thought. Garbage mechanic brings up an excellent point. It’s something I’ve wondered about. Flow. I know I originally tried to test the clutch with just a sheet of cardboard in front of the radiator. It led me to think about what I’ve got. I’ve got 3” of intercooler. I’ve got an AC condenser. That’s a lot of crap even with the cutouts in the bumper. There’s not much air going through the radiator up where the fan clutch is. There’s open space at the bottom. So the clutch may not be getting enough heat to actually lock the fan. That led me to try something.
This is I believe a motorcraft fan clutch.
This is room temp.
This is full travel. My temp gun says the spring is over 230 F. In our highly scientific measurement, it would seem that that thing would have to get really freaking hot if the heat is not transferring efficiently.
Also notice it only turns about 1/8 turn.
In the mean time, I pulled the new Horton clutch off the truck. I’m going to do the same thing to it to see where it locks up.
I’ll report later.
This is I believe a motorcraft fan clutch.
You must be registered for see images attach
This is room temp.
You must be registered for see images attach
This is full travel. My temp gun says the spring is over 230 F. In our highly scientific measurement, it would seem that that thing would have to get really freaking hot if the heat is not transferring efficiently.
Also notice it only turns about 1/8 turn.
In the mean time, I pulled the new Horton clutch off the truck. I’m going to do the same thing to it to see where it locks up.
I’ll report later.
bbjordan
Snow Monkey
^^^ the voice of experience.
When I was younger & dumber, I towed a 27' travel trailer across Canada to Newfoundland where I had to replace the transmission. The root cause of the problem turned out to be inadequate cooling due to plugged radiator cores. I discovered this after the automatic transmission was replaced, and the same symptoms started to pop up.
So this is what I found on the Horton clutch.
Here we have it cold.
Here we have it hot. It seems to start curling at around 120 and is full lock at around 160 F.
When I ordered it, I ordered the IDIT version which was supposed to come on sooner. My data would support that. I keep reading about people shortening the spring but looking at this, that would seem bass ackwards. Need to rotate the anchor point counter clockwise. Unless you cut an entire loop off it, I don’t see how you do it. Anyway. Not sure what I’m going to do. My plan A is not looking like it will be ready so probably going to have to go to plan B or plan C. I’m also looking at ways to force more air through the Rad.
You must be registered for see images attach
Here we have it cold.
You must be registered for see images attach
Here we have it hot. It seems to start curling at around 120 and is full lock at around 160 F.
When I ordered it, I ordered the IDIT version which was supposed to come on sooner. My data would support that. I keep reading about people shortening the spring but looking at this, that would seem bass ackwards. Need to rotate the anchor point counter clockwise. Unless you cut an entire loop off it, I don’t see how you do it. Anyway. Not sure what I’m going to do. My plan A is not looking like it will be ready so probably going to have to go to plan B or plan C. I’m also looking at ways to force more air through the Rad.
YJMike92
Full Access Member
Hm, it might be worth trying putting a match or grill lighter to the spring on the fan clutch while installed to see if it tightens up any as a means of testing.
EDIT: Tried it, no change. I did find the spring covered in oily dirt filth. I cleaned it up as best I could with a wire brush (looks like a big wooden handle toothbrush with metal bristles) while it's installed. The oily substance may be the clutch fluid leaking. It could be so caked with filth that it can't operate too. It's impossible to see while it's installed so I did the best I could.
No matter, I have a real temp gauge coming in the mail and I have a new Motorcraft fan clutch on hand already that I ordered a month ago, so if it needs changing, I can either do it myself or pay a shop if I can't get the old one loose.
EDIT: Tried it, no change. I did find the spring covered in oily dirt filth. I cleaned it up as best I could with a wire brush (looks like a big wooden handle toothbrush with metal bristles) while it's installed. The oily substance may be the clutch fluid leaking. It could be so caked with filth that it can't operate too. It's impossible to see while it's installed so I did the best I could.
No matter, I have a real temp gauge coming in the mail and I have a new Motorcraft fan clutch on hand already that I ordered a month ago, so if it needs changing, I can either do it myself or pay a shop if I can't get the old one loose.
Last edited:
The_Josh_Bear
Full Access Member
I saw a you tube video years ago about this concept of lazy Ford fan clutches, the guy just said they get stuck. Clean it up, drop some penetrating oil in there and turn back and forth like 40 times. Thanks to @laserjock for those close up pictures!
He also said if that doesn't work you could cut a new groove 90* from the OEM groove and re-clock the spring to help it come on sooner. Someone already mentioned this but I forget who, sorry for no credit.
For those of us that tow, either fix could be the ticket. I didn't try them as I switched to E-fans instead. They will never cool as well as the stock fan but for what I do they are enough(so far).
He also said if that doesn't work you could cut a new groove 90* from the OEM groove and re-clock the spring to help it come on sooner. Someone already mentioned this but I forget who, sorry for no credit.
For those of us that tow, either fix could be the ticket. I didn't try them as I switched to E-fans instead. They will never cool as well as the stock fan but for what I do they are enough(so far).
I had been staring at this trying to figure out how to adjust the spring to pin it closed essentially. That would do it! If it’s “reversible” on truck that could be my short term fix until plan A becomes viable. If it gets hot with the clutch locked, I’m pretty well screwed anyway.
79jasper
Chickenhawk
There's some literature out there about replacing the fluid for a more positive lock.
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Sent from my SM-N960U using Tapatalk
Yes. There’s also literature that talks about adding oil (assuming it’s not low on fluid) basically over fills the thing so that there is always fluid in the finned section inside which is what causes the friction between the halves. Switching that to a more viscous fluid I would think would have a more locking effect.
79jasper
Chickenhawk
I did the ole drill a hole and pin it with a bolt on a f800 5.9 Cummins today. Wasn't about to use $300 of my "allowance" on a fan clutch.
Truck was previously overheating, and the fan never locked up.
We'll see shortly. Lol
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Truck was previously overheating, and the fan never locked up.
We'll see shortly. Lol
Sent from my SM-N960U using Tapatalk
Funny thing, for heavy towing out to west Texas last summer I installed a fan clutch and fan on the shop truck. I drained all the fluid out of the clutch so it never locked up, just it spinning normal speed was more than enough to keep the ac and engine cool even with the big intercooler out front.
