Fan Clutch Symptoms? How loud is yours?

[levonhelm]

HI there, I've got a 91 3.0. My truck was always quiet, except right at cold start for a few minutes it would always sound like it's pushing tons of air.

I ran into the same problem driving back from a road trip, all of a sudden the clutch was locked on all the time. if my RPM's went up, so did the fan noise. I spent a long time sourcing out a new fan clutch, I ended up finding one that was apparently OEM spec, manufactured by NPW (nissan parts) roughly 130$ Canadian. (the cheaper ones were about 60$)

pulled the old one out, new one went in, when i swapped them i could feel the difference in how easily they would rotate, the old one was notably stiffer. I put the new one in and closed everything up and my fan clutch STILL DOES THE EXACT SAME THING!

any ideas??

 

[jgue467]

Not sure why a new one would stick like the old one.

Mine was starting to do the same thing but before replacing it, I simply spayed wd40 on the rusty coil spring pictured above and all has been well for a couple years now. The rust was preventing the spring from 'rotating' open/closed. Might try that. :cowboy:

 

[DontKnowRunner]

Fan clutch too loose? Engine and Tranny running above normal

Great thread!

My truck is running warm - engine seems to run b/w 194 and 204. Tranny never cools unless I'm going 45+mph. I know there's a lot to check out (rad cap, thermostat, etc.,) but it seems the fan clutch might be causing both?

On start, it runs fast for 10 seconds or so. I've never noticed it being loud at any other time - including when engine is hot.

Thoughts?

 

[.bg.]

Great thread!

My truck is running warm - engine seems to run b/w 194 and 204. Tranny never cools unless I'm going 45+mph. I know there's a lot to check out (rad cap, thermostat, etc.,) but it seems the fan clutch might be causing both?

On start, it runs fast for 10 seconds or so. I've never noticed it being loud at any other time - including when engine is hot.

Thoughts?

Those are normal operating temperatures. I wouldn't think there's a cooling issue unless you started to regularly see 215+ during regular driving. IIRC, the gauge won't even begin to move from the middle until you're over 230deg.

 

[DontKnowRunner]

Those are normal operating temperatures. I wouldn't think there's a cooling issue unless you started to regularly see 215+ during regular driving. IIRC, the gauge won't even begin to move from the middle until you're over 230deg.

Yep. Good to know. I've had my scangauge in for a year and a half. Until recently, the engine temps were routinely 190, and rarely over 194. No change in driving habits, so I figured something was up, just not sure what.

At the same time, I'm noticing that tranny never cools unless I'm going over 45mph, even with O/D off. This has been a problem on mountain roads where folks are driving slow, and the only way I can get the tranny to cool is to drop back and then speed up from time to time to 45 mph or more to get it to cool down some. I've only had the runner for a year and a half, so I'm not sure if this is normal or not, but I would expect the tranny to be able to cool itself - especially when over 210 and driving on a flat or stopped at a light from the fan. (I should have posted that in the original post too.) Tranny only cooling at 45mph doesn't seem right.

Grateful for any additional input,

Joe

 

[19963.4lsr5]

The reason it only cools above 45mph is because that's the mph the torque converter locks up. And it doesn't matter if OD is locked out or not. Which sucks. On my 04 grand Cherokee if I lock out overdrive the TCC locks up at 30mph. Which allows for a lot more cooling of the trans.


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[alumarine]

At the same time, I'm noticing that tranny never cools unless I'm going over 45mph, even with O/D off. This has been a problem on mountain roads where folks are driving slow, and the only way I can get the tranny to cool is to drop back and then speed up from time to time to 45 mph or more to get it to cool down some. I've only had the runner for a year and a half, so I'm not sure if this is normal or not, but I would expect the tranny to be able to cool itself - especially when over 210 and driving on a flat or stopped at a light from the fan. (I should have posted that in the original post too.) Tranny only cooling at 45mph doesn't seem right.

Grateful for any additional input,

Joe

It's because you've bypassed the cooler in the rad.

 

[DontKnowRunner]

It's because you've bypassed the cooler in the rad.

Thanks. I should update my sig. got a new rad last year. Tranny cooling system now goes through radiator and then through B&M.


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[alumarine]

Thanks. I should update my sig. got a new rad last year. Tranny cooling system now goes through radiator and then through B&M.

That is running warm then.
I rarely hit 210 towing a 3000 lb. trailer and then only briefly.
Once I start moving at all it drops.

 

[DontKnowRunner]

That is running warm then.

I rarely hit 210 towing a 3000 lb. trailer and then only briefly.

Once I start moving at all it drops.

So I'm thinking with both engine and tranny running warm, the most likely culprit would be the fan clutch or perhaps the new rad is defective


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[shahsmerdis]

Looks like I beat timmy the toolman before posting, but here is his video

https://www.youtube.com/watch?v=WzhlACxqeqQ If new, Everything answered there

there are a few signs to see if your clutch is getting old, no reason to play parts swap unless you are sure that is the reason.

 

[19963.4lsr5]

A lot of heat is put into the trans fluid when you driving around below 47 or so mph. Towing something makes it worse. How big of a cooler did you use?


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[DontKnowRunner]

A lot of heat is put into the trans fluid when you driving around below 47 or so mph. Towing something makes it worse. How big of a cooler did you use?

B&M 70268, 13,000 BTUs. I'm running in serial with the tranny cooler in the radiator. No towing, just two peeps in the Runner and no extra drag on top - no bikes etc.

 

[DontKnowRunner]

Looks like I beat timmy the toolman before posting, but here is his video

https://www.youtube.com/watch?v=WzhlACxqeqQ If new, Everything answered there

there are a few signs to see if your clutch is getting old, no reason to play parts swap unless you are sure that is the reason.

Thx, I've viewed the video several times.

Tried to stop the fan with rolled up newspaper while hot. Didn't stop the running fan - indicates fan clutch is ok.
When I shut the engine off while hot, it spins more freely than when I try to spin it cold - indicates fan clutch not ok.
Never hear the fan running hard while engine is hot - indicates fan clutch not ok.

I've got conflicting information here, but since both tranny and engine temps are higher than they should be, I'm inclined to go ahead and swap it out.

 

[shahsmerdis]

Thx, I've viewed the video several times.

Tried to stop the fan with rolled up newspaper while hot. Didn't stop the running fan - indicates fan clutch is ok.
When I shut the engine off while hot, it spins more freely than when I try to spin it cold - indicates fan clutch not ok.
Never hear the fan running hard while engine is hot - indicates fan clutch not ok.

I've got conflicting information here, but since both tranny and engine temps are higher than they should be, I'm inclined to go ahead and swap it out.

what are you saying is hot?
The other thing is what is the position of your tstat? if its not in the 6 oclock position then its probably runs ~10 degrees hotter than what some other people are reporting. I wouldn't worry about it. Just more heat for the winter

 

[19963.4lsr5]

You could try changing the plumbing so trans cooler is first. Is there mud or dirt or bent fins on the condenser blocking air flow?

Where is your trans cooler mounted? Mine is located to the left of center on the 97 puppy hauler. It's also larger at 21,000 btu. (TrueCool 4589)

Edit: your worried about trans temp, or engine temp, or both?


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[DontKnowRunner]

what are you saying is hot?
The other thing is what is the position of your tstat? if its not in the 6 oclock position then its probably runs ~10 degrees hotter than what some other people are reporting. I wouldn't worry about it. Just more heat for the winter

I should say hotter than previous. I'd call it running warm right now: Engine 194 - 204 sometimes 210. Tranny has been up to 220, and tranny temp never drops when I'm driving below 45 MPH, regardless of O/D or not.

I'm considering replacing the TStat as well, however since they're both in the high range, I'm thinking start with the fan clutch as it affects both systems.

 

[shahsmerdis]

I should say hotter than previous. I'd call it running warm right now: Engine 194 - 204 sometimes 210. Tranny has been up to 220, and tranny temp never drops when I'm driving below 45 MPH, regardless of O/D or not.

I'm considering replacing the TStat as well, however since they're both in the high range, I'm thinking start with the fan clutch as it affects both systems.

there is another video where timmy the toolman showed changing your tstat and radaiator cap dropped temp by 10 degrees. and changing fan clutch did nothing. I think tstat is your issue.

what is the outside temp btw?

 

[DontKnowRunner]

You could try changing the plumbing so trans cooler is first. Is there mud or dirt or bent fins on the condenser blocking air flow?

Where is your trans cooler mounted? Mine is located to the left of center on the 97 puppy hauler. It's also larger at 21,000 btu. (TrueCool 4589)

Edit: your worried about trans temp, or engine temp, or both?


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Both Trans and Engine are higher than they were when I started running the scangauge, and this is the 'cold season.'

Condenser is clean, only a smattering of bent fins. Trans cooler is mounted upper center left as you're looking at the vehicle from the front. It is definitely in the path of air, pulling from the fan.

 

[DontKnowRunner]

Attempting to replace the fan clutch, however, it appears the bolts have been previously tightened way past the recommended torque - SVM says 45 in/lbs. Sprayed with PB Blaster twice over the last 36 hrs, and allowed it to sit and penetrate to no avail I'm using the open side of a 12 mm wrench, and the corners are rounding. There's no visible corrosion on the nuts and bolts.

Ideas?