Aggressive fan clutch

[topher800]

Greetings,
  Two years ago we put in a new fan clutch with the water pump (and a new thermostat).  This unit seems super aggressive, and I feel like it works based on RPM instead of temperature.  It engages when I get below 2200 rpm and won't disengage until I rap it out to 4000 rpm.  My commute is country roads (sort of).  And it will do this all the way down into the 40's outside temperature wise.  My temp gauge needle has never hit the straight up mark.  Temperature gun looks good at the thermostat housing, ~170F.

The brand installed is a Duralast, it was all I could find on short notice.  Does all that seem normal?  Just get a new Behr?  Any thoughts...

Chris
 

[turbodan]

Sounds quite abnormal. They should freewheel with near zero drag until they start to see 140-150 degree temps coming off of the radiator. That's pretty much only a summertime thing.

[Shawn D.]

That's definitely abnormal.  My experience is as turbodan explains.

[gadget73]

yeah sounds stuck or just junk.  The original on my diesel was like that and it actually caused the water pump pulley to be destroyed.  It needed so much torque to drive that the bolt holes on the pulley ended up keyhole shaped. 

[Mike W.]

Fan clutches used to decouple at higher engine speeds rather than thermostatically. Even BMW used that on M30s thru '79. But I don't know if Duralast is even a manufacturer or just a rebrander, regardless, it doesn't seem to have the best reputation. Hate to say it since I've been known to go for the low buck stuff too, but sometimes there's a reason some brands are more expensive.

[gadget73]

Its Autozone's house brand, they don't make anything except boxes and money.  Who made it is hard to say but I'd guess Hayden if you made me pick someone to blame.   Hayden also usually has both a thermostatic and non-thermostatic version.  The cheaper non-thermo version is supposed to decouple at speed but if its made wrong it may not. 

[topher800]

Hate to say it since I've been known to go for the low buck stuff too, but sometimes there's a reason some brands are more expensive.

I have no issue shelling out extra $ for a better part.  You get what you pay for.  But this was all that was available on short notice.  In hindsight I should have put the factory unit back on.

BimmerWorld says the Sachs is on back order, with unknown arrival time.  They have a couple less expensive units.  Any thoughts on brands?  Irish Engineering has one.  OEM is super spendy....but I paid for the OEM radiator.

Thanks for replies so far

[Mike W.]

FPC has Febi/Bilstein for ~$100. Schiedmanns has several options I would at worst be willing to roll the dice on for less although with the current import status of things into the US who knows. I've had very good luck with my 2 or 3 orders from them, but again, today, who knows.

https://www.schmiedmann.com/en/bmw-E28- ... 62-catn-ol

[Etip]

Schiedmanns is good stuff. I got nice floor mats from them very cheap and shipped to US. 
With these fan clutches, I'm overwhelmed at the number of choices. I have a US spec M5 and they almost all say they fit it.  Which one to go with!!!????

[topher800]

I ordered the Febi/Bilstein that Mike recommended, from Schmiedmann's.  Arrived in about three weeks.  $42 + $24 shipping.

It went in fast as a fuse change.

Test drive today: sunny and 78F, it engaged some at traffic light waits.  Never roared like that other thing, full roar all the time from that.  Very happy so far.

 

[wayneoB7s]

i binned the  viscous  fan of  got sick of listening to the noise off it ... went to electric fan ... a worth while and cheap mod