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I've recently bought my 65 that seemed to need a new thermal clutch fan. Since install, I can't stand the roar coming from the engine compartment at freeway speeds. It's a stock 401 w/ac. Any suggestions? Thanks in advance Seafoam Don

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there are two basic types of clutch fans.

 

one is not thermostatically controlled.

 

the other ones are T-controlled, and these have a coiled spring showing at the front center of the clutch.

 

the T-controlled will kick back on if the radiator is getting too hot, then you will hear the roar start up again

 

Both styles can roar at cold start up but should get quiet in a few blocks.

 

Sounds like yours may be defective if it "never" goes quiet

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In addition to above info: Fan clutches are matched to the fan blade, engine rpm (gearing) and desired operating temp range. I once owned an '82 Suburban with the 6.2 diesel and HD cooling system. The factory thermal fan clutch worked so well, you might think it was being "switched" on and off. It only ran when pulling a load and then infrequently. The fan clutch was so well matched, at 8000 ft elevation or higher, it engaged and roared all the time at normal temperatures due to the thinner air and reduced drag on the fan blade.   The fan clutch is designed to work with the original OEM setup, changing the fan blade may change the operating characteristics. I would also question whether the replacement clutch is a good match or just calibrated for a wide range of vehicles.

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Thanks for the info men. I'll chat with my local parts guy to see if we can get detailed info about the replacement that they set me up with. Have a Great St. Patty's Day

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I've just started having the same roar at highway speeds on my 65 and it's really annoying like you say.

The fan clutch is about 3 years old and didn't do it until recently.

According to  the invoice it's a Haydon Part #2747 and a Thermal fan I believe because it has the coil spring.

Did anyone find a solution or has this one just failed?

Edited by fatbuick (see edit history)

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On 4/25/2016 at 3:25 AM, fatbuick said:

I've just started having the same roar at highway speeds on my 65 and it's really annoying like you say.

The fan clutch is about 3 years old and didn't do it until recently.

According to  the invoice it's a Haydon Part #2747 and a Thermal fan I believe because it has the coil spring.

Did anyone find a solution or has this one just failed?

 

Tony-

Yes, the Haydon 2747 has the coil spring on the front.  It's a good clutch.  They don't normally fail in 3 years.

 

On my '63, with the A/C running, in Texas where it is over 100 degrees, my thermal fan will cycle on and off, even at 60 MPH.  I can hear it go on and off.

 

Usually when these clutches fail, they stay off, not on.

 

If your clutch is on all the time, I'd look at the coolant temperature.  It may be hotter than you think and the clutch may be functioning correctly.

 

 

 

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Thanks Jim. It's winter here and I have a temp gauge so the coolant is definitely not above normal. Maybe the noise is something else but I've bought another lighter duty clutch Haydon #2705 and will give that a try soon. It also has a spring at the front but listed as Thermal whereas the #2747 is listed as Thermal Heavy Duty.

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Thanks again Jim. A great reference document.

Read the Troubleshooting Section and my symptom was there:

"Does not disengage - Fan clutch won’t slow down when engine is cold."

I'm looking forward to putting the new one on for quieter motoring.

 

BTW, Barbara and I have put our hands up to organise the 2017 Australian ROA Meet and we hope you and other ROA guys can make a special trip downunder. I will start a new topic when we have some firm details but it will probably be early May and close to Sydney NSW

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On 4/29/2016 at 10:33 PM, Jim Cannon said:

Jim,

  This is a great reference and confirms my experience with fan clutches. I have seen clutches which dont engage (due to fluid loss), stay engaged constantly no mattter what the temp (bad bearing or valving), etc...the statement in the reference which really caught my attention was in regard to some GMC truck replacement clutches being calibrated to engage at a lower temp than the OEM fan clutches. I went thru this many years ago after replacing the fan clutch on my `96 Suburban which I purchased new. I replaced the fan clutch as a preventive measure because I was doing the water pump. The first replacement roared for up to 10 minutes after startup when cold, even in the winter. The second replacement was a little better but clearly unacceptable as compared to OEM. The counter guys at my auto parts store thought I was crazy when I brought the second replacement back for exchange but I insisted on an AC Delco replacement. The OEM fan clutch performed as expected. BTW, still running the `96 Suburban in everyday service, my wife drove it from new, I drove it for a few years, all 3 of my children learned to drive in it and used it and now my daughter uses it every day as an urban assault vehicle back and forth to college, it now has 330K miles on the original engine and trans and gives no signs of giving up! 

Tom

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The 330K just goes to show what's available with the right kind of maintenance in knowledgeable hands.

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On ‎4‎/‎30‎/‎2016 at 9:04 AM, RivNut said:

The 330K just goes to show what's available with the right kind of maintenance in knowledgeable hands.

 

Plus a bit of 'luck' with regards to the quality of the vehicle when manufactured.

 

Steve

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