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Engine cooling fan

5K views 21 replies 7 participants last post by  JER-1 
#1 ·
So recently temps here in central California have been climbing and I've been working the truck a little more and I'm realizing the fan does not come on like i think it should.

A little background on the truck-

I bought it at Christmas time 2016 with 133k

Came with receipts showing a radiator, shroud, fan, and clutch installed at 128k. Everything was replaced with oem motor craft parts.

Truck now has 149 on it, but I don't think the fan has ever come on. I haven't ever gotten it hot enough to even make me think about it until recently. I have seen the temps hit 226 ect, oil was right around 235.

Here's where it gets weird. The fan never came on solid, it would kick on for about a second, never more than two seconds. I did a little research, hooked the dark blue wire to ground to force the fan clutch to 100%. I don't have the equipment to confirm the % of engagement, but it comes on strong, very loud and annoying. I am assuming I am getting good engagement.

So it seems that the clutch itself works, what else could be my problem? With the ground hooked up, the fan works and doesn't shut off at all, ran it for probably 6 hrs on the freeway the other day, 115 outside and it was hardly running 195 with the ac blasting at 75 mph.

Fan seems to work lol. I just want it to work the way it is suppose to.
 
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#2 ·
An Android phone or tablet with the Torque app would let you see fan RPM. It's a cheap solution, if you want to have a bit more of a quantitative grasp of your problem and solution.

Go here to get a wiring diagram for your truck: http://www.powerstroke.org/forum/ge...res-single-page-6-0l-wiring-diagram-pdfs.html

Since you didn't tell us what year, I can't look at your specific wiring diagram but - regardless of year - I would expect that you have a harness issue between the fan clutch connector and the PCM. It could be at the PCM connector itself or inside the harness along the run.

Here is a link to a thread on chafing: http://www.powerstroke.org/forum/6-0-motor-problems/1096562-6-0-harness-chafing.html

I would:
  • look for chafing,
  • wring out - using a meter - the fan wiring, or
  • run separate wires from the PCM to the fan to see if the fan works properly.
 
#3 ·
Thank you for the quick response! I got distracted by having some trouble typing on my phone, sorry I left out some details...

The truck is a 2003 f350, it has been studded and egr deleted (I set an old egr valve on the intake and plugged it in, no egr codes). Has 4" exhaust with just a magnaflow muffler, no cat, edge evolution programmer (would be a sct if I wasn't worried about this fan problem at the moment).

I will look into the torque app and read those threads shortly. Thank you for your suggestions.

One more thing to mention, there were no codes for the fan prior to grounding it to force it "on".
 
#4 ·
The clutch on my 04 had the same exact symptoms. When the truck got hot it would come on loudly for a second or two but then shut off again. I replaced the clutch and all was well for a couple years but it slowly started to run for shorter and shorter periods until it got back to running for only a second or two. Not really sure what was going on but didn't want to buy another one and have it crap out again so I went with the 7.3 mechanical clutch and BPD adapter. It works great and I'm a lot happier with how the truck manages it temps now.
 
#22 ·
This above I did same, one of best mods out there, for couple hundred bucks
Jer
 
#5 ·
My brother has the "torque" app on his phone, I will be checking fan speed with it tomorrow after work. I don't think that is going to reveal my problem.

I tracked down the blue wire at the pcm, it seems to have a good connection all the way to the jumper I made, with the jumper disconnected from ground of course.

I can trigger it to come on with the jumper, so I know the connection is good down to the clutch.

Does anyone know where I might find the "efc module"? I'd like to check any wires that connect to it for chafing as well.
 
#8 ·
I'm not saying that the Torque app will help you find your problem. ...only that it might help you to know if you found your problem. If you are getting 400RPM now at 210F and you get 1400RPM after repairing some wires, that would be a good thing.

The EFC is in the fan clutch, AFAIK. I was thinking that you would find a problem with that blue wire traced back to the PCM. Hmmm... Must think...

Attached is the Ford Pinpoint Test (AH) for the fan clutch, in case it helps.
 

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#6 ·
DMC, thanks for your response and sharing your experience!

Did you happen to test that clutch by grounding the blue wire?

I don't know if that is any kind of reliable test, but mine seems to run fine that way. I was thinking that it indicated it was good, but now that I'm thinking about it that may narrow it down to one of the pulse wave wires at the clutch... I really don't understand how it works, just that it does when I ground it. Haha.
 
#7 ·
Yes, I grounded it. Even put a switch in the dash so I could control it manually. It worked fine that way but I just got tired of monitoring it and turning it on at the right times so that's another reason I went with the mechanical clutch.
 
#9 ·
DMc, thanks again for your insight, it looks like I'll be replacing the clutch... buuuut, the combination of being able to turn the fan on when I need to, having some free time, and being stubborn about spending money is driving me towards wanting to thoroughly diagnose this thing til I either pinpoint the problem or get bored of it. Lol. Based on your experience I think replacing the fan clutch would repair it. Please don't take any direspect by me troubleshooting other areas before I admit defeat.
 
#10 ·
Djmaguire, thanks again for your insight. I was also hoping that I'd find a problem with the blue wire.

I get what you mean about confirming a fix with the torque app, I'll be sure to record what I find.

Something to consider is that I haven't gotten any codes about the fan speed until I grounded the blue wire, which could suggest the pcm never commanded it on?
 
#11 ·
Yes to your comment about the PCM. Is there any custom tune on that truck? I can't imagine that anyone would mess with the fan logic but, who knows?

You have the EGR valve plugged in. The jury is out on whether the EGR valve being unplugged messes with fan logic but - if it wasn't already plugged in - I would've recommended that.

Gotta think more. You could put a bulb between Vpwr and the blue wire and watch for brightness changes to see of the PCM is trying to command it or not.
 
#13 ·
I - for one - am prolly gonna do that. I have one diabolical experiment left to do on my Viscotronic fan clutch first, though.

Damn my dedication to the advancement of science and my obligation to the world to learn the secrets of the 6.0. It's a curse, I tell ya...
 
#14 ·
I did my final "diabolical experiment" to my Vistronic fan clutch...



We had a disagreement as to whether it was coming off the truck or not.
I won
 
#16 ·
Definitely wanna look at fanvar duty cycle. Honestly, I usually need to get these turkeys eot up to 230-240 before that fan comes on full
 
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#17 ·
I have been wondering what the true threshold was. 230-240 before full on is just freaky. I want to be hearing intervention at 215.
 
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#18 ·
I know there's more to it than just ECT but when mine was working, it would wind up at 218 and bring the temp below 200 before shutting off. But when it started short cycling it had no effect on temps at all since it didn't run long enough.
@O36O - No disrespect here. I was in the same boat as you and it took me a while to admit defeat too!
 
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#19 ·
So I got the torque app stuff from my brother. So far I've just confirmed what I already thought. At idle It runs approx idle speed, if I raise the idle it speeds up at first, then drops off. When I ground it, it runs just above engine speed. Around 2000rpm fan speed at 1500 rpm engine speed. Seems to confirm that the clutch locks in tight.

Maybe the failure happened in the pulse wave wiring/efc module?

I have the torque app plug for a few days. I'll download the app to my phone and monitor things for a while and see if anything interesting happens.

If anyone thinks of anything else to check/monitor im all ears, I wouldn't mind learning more about it.

Thanks for all the help so far guys, I really appreciate it!
 
#20 ·
Well, itching new with my fan issue. I just ground it when I need to, it's not too bad. I would much rather have it work the way it's intended to though. Lol

I got a sct x4 programmer since I started this thread. Going from the edge evolution to sct made no difference with the fan (as expected, I had already used each different tune on the evolution-none had any affect on the fan). Definitely makes more power, and is much more drivable when it's turned up compared to the edge.

As a side note however, the trans tune doesn't seem to be what I hoped for. With the edge (it does tune the trans) I had crisp clean shifts. With the sct, I've been getting a flare between 3-5. This goes against what everyone else claims with a sct. Thoughts?
 
#21 ·
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