New OEM fan clutch but still roaring dump truck?

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Your thread focuses on several factors:

MPG issue is related to bigger wheels, heavy front bumper etc., I am fully stock 265/75/16 (38 PSI), stock bumpers and I get 16 to 18 MPG on highway.

I have a brand new Radiator (Denso), fan blade (AISIN), fan bracket (OEM) and fan clutch (AISIN): On cold start I hear the fan spinning but it is never loud: If I let idle for about 5-7 minutes, I hear the clutch engaging by roaring sound. When I drive off at cold or after warming up, I never hear the sound inside the cabin.

When cold, I can spin the blade about 1-2 blades. If you pull harder, I may get to 3 blades.
HAve you clean the AC and radiator fins?
 
Joined
Jun 6, 2022
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Location
Arizona
Your thread focuses on several factors:

MPG issue is related to bigger wheels, heavy front bumper etc., I am fully stock 265/75/16 (38 PSI), stock bumpers and I get 16 to 18 MPG on highway.

I have a brand new Radiator (Denso), fan blade (AISIN), fan bracket (OEM) and fan clutch (AISIN): On cold start I hear the fan spinning but it is never loud: If I let idle for about 5-7 minutes, I hear the clutch engaging by roaring sound. When I drive off at cold or after warming up, I never hear the sound inside the cabin.

When cold, I can spin the blade about 1-2 blades. If you pull harder, I may get to 3 blades.
HAve you clean the AC and radiator fins?
The only reasons I mentioned several issues are because:

1. A locked up fan clutch is supposedly adversely affects mpg and engine power

2. Someone in a different thread had mentioned that after changing his fan clutch, his perceived transmission issues were gone too. I wanted to post about the transmission issue in a separate thread but didn’t know whether a locked up fan clutch which causes loss of power would cause perceived transmission shifting issues.

3. I do hear loud roaring in the cabin after driving a few minutes. Like I said, none of the other vehicles I’ve owned, including the one that had the same exact engine and transmission, ever sounded like a dump truck, in az summer heat.

It seems it’s common consensus that the dump truck like roaring is caused by a locked up fan clutch. I was baffled by the fact that changing out the fan clutch did not solve the problem and therefore wanted to see whether there’s any other insight.
 
Joined
Sep 9, 2016
Messages
2,316
Location
Odessa/Midland TX
The only reasons I mentioned several issues are because:

1. A locked up fan clutch is supposedly adversely affects mpg and engine power

2. Someone in a different thread had mentioned that after changing his fan clutch, his perceived transmission issues were gone too. I wanted to post about the transmission issue in a separate thread but didn’t know whether a locked up fan clutch which causes loss of power would cause perceived transmission shifting issues.

3. I do hear loud roaring in the cabin after driving a few minutes. Like I said, none of the other vehicles I’ve owned, including the one that had the same exact engine and transmission, ever sounded like a dump truck, in az summer heat.

It seems it’s common consensus that the dump truck like roaring is caused by a locked up fan clutch. I was baffled by the fact that changing out the fan clutch did not solve the problem and therefore wanted to see whether there’s any other insight.
This may sound simple, have you clean the radiator/AC condenser/Trans cooler fins? If you place a work lamp inside the engine bay, next to the fan, can you see it from the front of the LC? Must be able to see light even though the trans cooler. LIke I said, my fan clutch also soins like yours, but does not sound too loud.

The 4R with V8 has a smaller radiator and possibly a smaller fan/blade.
 
Joined
Feb 13, 2022
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Location
Houston, TX
My 2006 lc has always been loud on startup and and I too replaced the fan clutch which didn’t make any difference.

I forget how many rpms it revs to on cold startup but it quiets down after a couple three minutes.

I have a coworker with a 2007 lexus 100 and his doesnt roar like my 2006 - both vvti but there is obviously a noise diff on cold start.
Should be around 1000-1200 rpm cold start. Will keep dropping in seconds.
 
Joined
Jun 6, 2022
Messages
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Location
Arizona
You think you'll be able to capture the sound with your phone while driving?
First one after the cool morning 12-mile commute today just pulled into the garage at work. I rolled the DS front window down to get a better recording of the roar as I went above 2000 rpm while parked.



Second one leaving work late afternoon a few minutes after starting driving. No roaring. Everything was quiet.



Last one when I got home after the 12-mile commute back - fan roaring. All windows were rolled up. Today’s high was a mere 98 - really cool for AZ summer.

Fan clutch roaring after 12-mile commute back home with a cool high temp of only 98 in AZ

Fan clutch roaring after 12-mile commute back home with a cool high temp of only 98 in AZ - https://vimeo.com/751923717
 

Red Beard

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First one after the cool morning 12-mile commute today just pulled into the garage at work. I rolled the DS front window down to get a better recording of the roar as I went above 2000 rpm while parked.



Second one leaving work late afternoon a few minutes after starting driving. No roaring. Everything was quiet.



Last one when I got home after the 12-mile commute back - fan roaring. All windows were rolled up. Today’s high was a mere 98 - really cool for AZ summer.

Fan clutch roaring after 12-mile commute back home with a cool high temp of only 98 in AZ

Fan clutch roaring after 12-mile commute back home with a cool high temp of only 98 in AZ - https://vimeo.com/751923717

Oh wow. So it looks like you get that “dump truck” noise when the engine is heated up?

What’s weird is, for me it’s been the opposite. I’ll get the loud fan at start up but once it’s warmed up for 1-2 mins, it goes quiet again while driving or revving as you did.
 
Joined
Dec 2, 2015
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arizona
Pull the fan and clutch off and drive it around. That'll tell you if it's the fan/clutch combo or something else.

Jim
 

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