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Discussion Starter #1
Hey guys

Comparing my car and my uncle's Allroad, I see that when he builds the engine RPM's up, the rad fans increase speed. My car doesn't do that and no matter what RPM you're at it stays the same speed.

Car never overheats and is always at 90c (~190F) at full running temperature.

Are these fans suppose to increase/decrease speed with engine RPM (I am NOT talking about the AUX electric fan)?

Thanks,
Elliott
 

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it will if it needs to, its a clutch type fan that senses heat coming off the radiator, when the heat increases enough the fan speed increases as needed thus pulling more air to cool it down then the clutch loosens up and the fan slows down. now if youve been running the ac and its not that hot out the clutch fan may not need to be engaged that much, mine on the other hand i dont use ac that much so the aux fan doesnt run that often and i hear my clutch fan pulling a lot more air than it does when its cold out.

now your fan clutch could possibly be toast and not engaging but you would start to see temps climbing and possibly the aux fan kicking in without the ac on. on the other hand these clutches can also seize in the "locked" position which might be the case on the allroad that you're hearing it more often, this doesnt hurt much, but can decrease MPG and put un-needed stress on the front accessory drive

what are your ambient temps like? are you using the air con? how long do you drive at a time when you are not hearing the fan change speed?
 

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Discussion Starter #3
it will if it needs to, its a clutch type fan that senses heat coming off the radiator, when the heat increases enough the fan speed increases as needed thus pulling more air to cool it down then the clutch loosens up and the fan slows down. now if youve been running the ac and its not that hot out the clutch fan may not need to be engaged that much, mine on the other hand i dont use ac that much so the aux fan doesnt run that often and i hear my clutch fan pulling a lot more air than it does when its cold out.

now your fan clutch could possibly be toast and not engaging but you would start to see temps climbing and possibly the aux fan kicking in without the ac on. on the other hand these clutches can also seize in the "locked" position which might be the case on the allroad that you're hearing it more often, this doesnt hurt much, but can decrease MPG and put un-needed stress on the front accessory drive

what are your ambient temps like? are you using the air con? how long do you drive at a time when you are not hearing the fan change speed?
Thanks for the write-up.

Ambient temps are about 87-90F. AC on or off doesn't matter. Driving the car I don't hear fans speed up like the Allroad does. I dunno maybe it's normal for that car to do that.

It's also very possible that the clutch on my fan is toast...I never hear it speed up or slow down + car has 227k miles on it now.

Thanks again,
Elliott
 

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yeah i would say at that mileage swapping the fan clutch out for a new one wouldnt be a bad idea, definitely cheap insurance compared to when you might really need it to engage and risk the engine overheating, but thats just me, i'm big on "preventative maintenance", its usually cheaper to fix before it breaks as things tend to take other things down with them
 

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Discussion Starter #5
So it is the clutch I should be swapping out and not the whole thing? What's the diff between these first 4?

OEM / Performance Parts for Audi, BMW, Mercedes Benz, Mini, Porsche & Volkswagen - ECS Tuning

Why the big price difference for the 4th one?

Volkswagen Passat B5 FWD 1.8T > Search > Fan Clutch > ES#2090861 Radiator Fan Clutch - 058121350

But just a question: when you guys rev your engines when the car isn't moving how long does it take for the fan to speed up? Instantly? If so, then I need to fix something. If you need to rev it for a while for it to do anything then maybe mine is still good
 

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I think that 4th one is just a cheaper brand, I'd personally go with the sachs, of those it is the only one that sounds like a reputable brand, and 100 bucks is average for a good fan clutch, also try rockauto.com

The fan will not speed up instantly but it is pretty close, and it will really only speed up noticeably if the engine is less than about 2500 rpm (2000 is where it really starts to be noticeable) but above that the pulley spinning too fast and the clutch can't really hold it so it slows down relative to engine speed, try holding it at about 2000-2200 rpm after you've been driving it for a while, probably 20 minutes should do it, if it can tighten up, it should by then and you'll hear it, it's not like a big rig but it is noticeably louder
 

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Discussion Starter #7
Okay thanks I'll try it out and post back.

Can the clutch be replaced without going into the service position?
 

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On my V6, the thread is left handed, righty loosey, lefty tighty. You should be able to do this without putting the car in service position.
 

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Discussion Starter #10
Thanks guys. Just an update:

Is the thread left handed like GSO_Passater says or is it normal thread? I was looking at where you're suppose to use the fan wrench and on my car it seems like the whole thing is round...no flat sides for a wrench to fit on! But I'll have to get a better look at it soon.

I will be performing this procedure soon...hopefully the bolt on the back side of the clutch isn't frozen in place after 227k miles...:(
 

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Discussion Starter #12
Well weird thing was that my original fan (or old fan? not sure if it was ever replaced during the life of the car) didn't have the hex fan clutch nut.

Anyway it's swapped out and running good now!
 
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