Motorcraft fan clutch no good

[Matt_INW]

I should have verified the clutch was no good when I installed it a year ago. But I replaced the entire cooling system and anytime the truck got to 190-195 or so the thermostat opened, it never got to 200. It does provide resistance when I manually turn it with the truck off, it doesn't freewheel. But it never locks, ever.

I didn't worry about the clutch, until today towing a 5th wheel at 9-10k a couple hundred miles each way on a mini vacation.

Darn coolant temp for up to 235 on one pass and 233 on another. Fan clutch never engaged. I have an after market coolant temp gauge that's both analog and digital, so the aforementioned temps are exact, at least at the spot the sensor was added. The OEM gauge got a bit warmer than usual but happily stayed midway in the normal range.

Anyways!

I know I recall reading something about pulling out the coil and bending it to make it engage sooner. But I can't find the specifics, but one post that said to actually pull it partially out and bend, vs bending farther towards the middle. I looked through the tech articles and have tried a general search too. Maybe my search voodoo sucks tonight. Is there someone who can specifically say which direction to move the bend, and how far down is right? And do I use RTV to put the end back in or something else?

 

[79jasper]

@icanfixall

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[Matt_INW]

Ok found the following thread and read most of it. So hopefully there is a decent length of coil on the end of mine. I take the outer end of the coil our, then need to "move" the bend close to the end of the coil (1/8-1/4 inch) and put it back in and RTV it. Some people have had success, one person broke it, another said no change. Hopefully it works for me, I hope to try it tomorrow, will see depends on how my neck and back are doing (currently both are out, yay).

http://www.thetruckstop.us/forum/threads/diy-fan-clutch-mod.12265/

 

[chris142]

New does not mean it good. We stopped using Hayden fan clutches because they just suck! Us motor works seem to be much better and more aggressive

 

[Matt_INW]

@chris142, sad but true. How much for the US motorworks? I went to their site but looks like I need to be a business to register....

 

[chris142]

Your in luck! Autozone sells them

 

[MTKirk]

Your in luck! Autozone sells them

A quick look on the Autozone website turns up a duralast brand fan clutch only, is this a re-branded US-motorworks? http://www.autozone.com/cooling-hea.../duralast-fan-clutch/77869_0_0/?checkfit=true

 

[chris142]

Yes. its a USMW part in their box

 

[OLDBULL8]

It's not the engine temp that kicks in the fan, it's the air temp coming off the rad. Most fan clutches kick in at 240. That Bi-metal spring is tempered, so it can break off easily when bending. Clean it off with Brake-Kleen, any dirt on it acts like insulation. If your gonna shorten it, make sure you know which way to put it back in.

If your Rad is full of bugs, or anything in front of it, give it a good water hosing out, the clutch needs good air flow. Clean it from inside out first.

 

[Matt_INW]

If the fan clutch kicks in at 240, and the engine overtemp is 240, something is wrong? If I shouldn't worry about 240 then I can let it be but... I have no desire to kill the truck when I tow in hotter weather (was only 70 or so).

Everything is clean, no bugs etc, all new last year, still all looks new with only a few thousand miles since install.

 

[icanfixall]

The sender located in the drivers side front of head is the over temp sender. When the engine reaches 242 degrees this sender will ground and send the dash gauge way past the "L" in normal. To test this remove the wire to it and ground it. the dash gauge must swing way past the "L" no matter how hot or cool the engine is.
As posted. New does not mean good. If you are worried about bending the spring there is not much to worry about. Just find a wrecker and remove the spring from a like fan clutch. Might want to do this as practice too. Also ANY dirt on the spring is clear proof the seal on the shaft has failed. No amount of re bending will change anything. A store in Babalyon New York called MS Tech sells a modified fan cluth where they re bend this same spring. They are expensive for what they do too but I have run them for years on my rig and really like them.
Yes... It would be great if 220 to 230 is where we could ALWAYS get cooled down from but for me I feel thats near the death area and do not like to make excursions that close to 242 degrees. Some members have told me we can run at 240 degrees and on the red line all day long.. Not for me either but these are truck engines made for the real hard life..

 

[Matt_INW]

Well it took until about 7:15pm but I got the replacement fan in. Turns out it wasn't motorcraft, they don't make them anymore. It was NAPA, and it had a lifetime warranty, so put in the replacement one.

Then since it's cool I put the cover on the grill usually reserved for freezing temps and totally closed it off. Drove it at 55-60 with OD off, even then I could only get it to 204, a couple moments 2 times at 205 an 206. But right about then I heard the fan! Woowoo! I don't think it was fully engaged, but it was partially engaged. I'll still feel better hearing it fully engaged in warm weather, but I do think it's working, unlike the previous one.

 

[icanfixall]

There is nothing like the sound of the fan engaging when temps come up. I have pulled several of the grades in southern ca and heard the fan engage. then watched the temp come down as I was still climbing the same grade hauling a tailer. Hard to believe but it is the truth.
Glad you found the cooling issue and fixed it free too...

 

[MTKirk]

Well it took until about 7:15pm but I got the replacement fan in. Turns out it wasn't motorcraft, they don't make them anymore. It was NAPA, and it had a lifetime warranty, so put in the replacement one.

Then since it's cool I put the cover on the grill usually reserved for freezing temps and totally closed it off. Drove it at 55-60 with OD off, even then I could only get it to 204, a couple moments 2 times at 205 an 206. But right about then I heard the fan! Woowoo! I don't think it was fully engaged, but it was partially engaged. I'll still feel better hearing it fully engaged in warm weather, but I do think it's working, unlike the previous one.

What brand/part number did you end up getting?

 

[Matt_INW]

The NAPA part number is 273399, NAPA TEMP is apparently the maker of it or at least re-branded as them.

Aha, found a wiki page for Standard Motor Products. Which says the stuff it makes is re-branded as NAPA Temp, and Murray and Duralast, several others. So Standard Motor Products might be the true manufacturer.