Is my fan clutch bad?

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2018 Toyota Tacoma 2.7 4 cyl just hit 20k miles. Out of 36/36 warranty.

Trying to figure out if my fan clutch is bad or not before I buy a new one. I’m getting different answers everywhere I look.

I’ve tested my fan clutch a few times. When engine is cold it has pretty good resistance. It does not free-wheel at all. There is enough resistance that when I stop pushing the fan stops spinning almost instantly. When engine is hot, there is slightly more resistance but not much.. From what I’ve read, resistance is good and normal.

The issue lately is that the fan has constantly been loud(howling noise, like the garbage truck). I’ve heard that this is normal for Toyotas so I never though much of it until a friend pointed it out. His tundra 5.7 doesn’t do it. It’s the same “howling” noise when you first start up, but it never goes away. Even after driving for 45+ minutes. Hot OR cold ambient temperatures.

This is when it all starts to make sense.
-My AC warms up when idling for more than a few minutes
-takes forever to warm up in the winter.
-I get 8 cylinder MPGs in a 4 cylinder(14.5 winter, 18 best during summer when rated 19/22).
-all YouTube videos of the 2.7 accelerating sound like a 4 cylinder engine, mine sounds 100% fan and 0% engine.

I’ve done 10k miles since I brought the truck. I could’ve sworn the fan wasn’t as loud as when I first got it. I know there are some other 2.7 owners on here. Can anybody confirm if this is normal?
 

BlueOvalFitter

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When I start my truck the fan clutch definitely lets you know it's there. As I begin to drive, engine not up to operating temperature yet, the fan clutch really comes alive! As the engine warms up the fan clutch noise tapers down.
 

JHZR2

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Sounds like it's too aggressive. That should make the ac work well though.

Agree.

Fan clutch shouldn’t be pulling the fan a lot until it gets good and hot, based upon air coming through the radiator. On a cold engine it shouldnt engage.

I can tell when it goes on and off on my Ram Cummins 4x4, but my other vehicles with fan clutches, I cannot…
 

avacado11

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When I start my truck the fan clutch definitely lets you know it's there. As I begin to drive, engine not up to operating temperature yet, the fan clutch really comes alive! As the engine warms up the fan clutch noise tapers down.

If I remember right that’s how mine was last winter. I just find it odd that the noise doesn’t go away fully warmed up and above 3000rpm. Anything below the fan isn’t noticeable once it’s warm.

That’s why I concluded it was normal for all of this time until someone pointed it out. Then I realized most of the other 2.7s don’t sound the same under full throttle
 

avacado11

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Sounds like it's too aggressive. That should make the ac work well though.

That sounds about right. I figured with a mechanical clutch it was bound to warm up at idle since it isn’t pulling as much air until RPMs is up. Hence I didn’t think twice of it.

I hear conflicting reports saying the fan should or shouldn’t have resistance. Some say it should be fairly loose. Some say it shouldn’t. Which is it?
 
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I've had fan clutch trucks and when I stop the engine after "normal" driving (eg <70'F not in traffic) I can see it coast/ spin down on its own and there's very little resistance.

On cold start they usually loosen up and stop that school bus noise by about 3rd gear or 1/10 mile from home.
 
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Is it the original fan clutch or aftermarket? I bought an aftermarket Beck/Arnley fan clutch to replace my 260k mile OEM one and I bought the aftermarket because it was cheap and "Made in Japan". After installing it was louder than the stock one, and after I did some research I found the exact same clutch that someone took apart and it was completely hollow! It was basically welded together and was always on.

I bit the bullet and bought a $220 OEM nissan clutch and the difference is night and day.

 

avacado11

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Is it the original fan clutch or aftermarket? I bought an aftermarket Beck/Arnley fan clutch to replace my 260k mile OEM one and I bought the aftermarket because it was cheap and "Made in Japan". After installing it was louder than the stock one, and after I did some research I found the exact same clutch that someone took apart and it was completely hollow! It was basically welded together and was always on.

I bit the bullet and bought a $220 OEM nissan clutch and the difference is night and day.


OEM Aisin clutch. They’re running about $175+ at the moment. Ordered a $50 Hayden off rock auto while I take apart the OEM one and try to see if anything’s jammed up. Most likely it is. If it doesn’t go back together atleast I’ll have a spare sitting around.
 
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I don't think it could be anything else, maybe temp sensor saying the engine is hotter than it is?

The loud fan at all times thing is almost always the fan clutch.
 

avacado11

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I don't think it could be anything else, maybe temp sensor saying the engine is hotter than it is?

The loud fan at all times thing is almost always the fan clutch.

Pulled it apart and it’s a seized bi metallic strip on the clutch. Could not get it to move at all.

Now the issue is that the 4 bolts holding the clutch on keep getting stripped by a boxed end wrench. There’s not really any other way to get it out and 6 point 12mm boxed are nowhere to be found.

So a Toyota with a broken part that doesn’t come off smh.
 

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Pulled it apart and it’s a seized bi metallic strip on the clutch. Could not get it to move at all.

Now the issue is that the 4 bolts holding the clutch on keep getting stripped by a boxed end wrench. There’s not really any other way to get it out and 6 point 12mm boxed are nowhere to be found.

So a Toyota with a broken part that doesn’t come off smh.

6 point 12mm wrench

The fan clutch on my Jeep roars for the first 30-45 seconds of driving any time it sits for more than an hour. The way I understand it, it's got something to do with the silicate or whatever makes the fluid coupling work settling while sitting and taking a few moments to "disperse" throughout the clutch. I'm just glad I don't have a newer WJ with the much-maligned hydraulic cooling fan setup. That was a real disaster.
 

avacado11

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6 point 12mm wrench

The fan clutch on my Jeep roars for the first 30-45 seconds of driving any time it sits for more than an hour. The way I understand it, it's got something to do with the silicate or whatever makes the fluid coupling work settling while sitting and taking a few moments to "disperse" throughout the clutch. I'm just glad I don't have a newer WJ with the much-maligned hydraulic cooling fan setup. That was a real disaster.

Had my mechanic throw on the new clutch today. With the correct tools he was able to do the whole job in less than an hour.

From everything I’ve seen about these thermo fan clutches, the metallic strip will expand/contract to control how much silicate pressure there is on the clutch. This would mean it’s loud at start up, then gets quiet, then loud again once hot.

This logic doesn’t make much sense on my Toyota. It is loud when starting up. Quiets down within a few seconds. But from there on wether it’s 5 minutes or two hours, any time RPMs above 3000 the fan is loud again. Almost like the clutch was never designed to run above that RPM. From every 2.7 accel video I’ve seen there is no pronounced fan noise. It is 45 degrees out today. It’s slightly quieter now but still pronounced.

Could a bad idler pulley cause a howling like noise? I’ve only ever heard a bad pulley whine.
 

avacado11

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Here is a video of my truck and said noise. New clutch is slightly quieter, but still making the same noise. Did I just get a defective new fan clutch?
 
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Pulled it apart and it’s a seized bi metallic strip on the clutch. Could not get it to move at all.

Now the issue is that the 4 bolts holding the clutch on keep getting stripped by a boxed end wrench. There’s not really any other way to get it out and 6 point 12mm boxed are nowhere to be found.

So a Toyota with a broken part that doesn’t come off smh.
You need a flank drive + snap on wrench
 
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Had my mechanic throw on the new clutch today. With the correct tools he was able to do the whole job in less than an hour.

From everything I’ve seen about these thermo fan clutches, the metallic strip will expand/contract to control how much silicate pressure there is on the clutch. This would mean it’s loud at start up, then gets quiet, then loud again once hot.

This logic doesn’t make much sense on my Toyota. It is loud when starting up. Quiets down within a few seconds. But from there on wether it’s 5 minutes or two hours, any time RPMs above 3000 the fan is loud again. Almost like the clutch was never designed to run above that RPM. From every 2.7 accel video I’ve seen there is no pronounced fan noise. It is 45 degrees out today. It’s slightly quieter now but still pronounced.

Could a bad idler pulley cause a howling like noise? I’ve only ever heard a bad pulley whine.
I would be more suspect of the Hayden fan clutch you bought, but I would also give it a week. From everything I've seen, fan clutches are like good speakers. They need a little time to break in after manufacturing and shipping.
 

avacado11

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I would be more suspect of the Hayden fan clutch you bought, but I would also give it a week. From everything I've seen, fan clutches are like good speakers. They need a little time to break in after manufacturing and shipping.

Guess all it needed was a break in. It’s been much quieter on the highway then it was before. Engine RPMs and shifts are much smoother. Less vibration above 3000rpm. The shifts used jerk. I assume because the engine was always under load from the fan and it threw the trans out of wack.
 
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