Aftermarket vs OEM Clutch Fans

drivetolive · 07-27-2010, 12:04 AM

So I had my clutch fan replaced with an aftermarket one a couple of months ago and the dam thing won't turn off (very annoying). It's on all the time, makes my car sound like a big rig. Even when I start it (cold start) it comes on full blast and than gradualy slows down as my car warms up. But regardless of whether my engine is hot or cold, I could hear the fan (it's really loud).

On a cold night, it's not as loud but still noticable. On a hot summer day (like today) it's on full blast.

My friend's exact same car doesn't have the same "problem".

I've had some people say it's not normal, others say it's normal, while others say it's happening because it's an aftermarket clutch fan.

I've asked numerous people and can't really get a clear cut answer. Would replacing it with an OEM clutch fan prevent it from being on all the time? Want to make sure before I shell out the $300 for an OEM one.

zarbat007 · 07-27-2010, 12:49 AM

What brand is it?

///Mmm · 07-27-2010, 01:25 AM

The OEM fan clutch should only engage when the engine temp gets high ,usually in traffic or a really hot day.

The way your current fan clutch is acting is not normal, i suggest you change it.

Call any of the sponsor shops, they should confirm this.

Bimmer Heaven · 07-27-2010, 02:09 AM

Yes, not normal at all! Take it off before it fully locks up and BAD things happen! (trust me on that, too many horror stories!). If you dont want to spend that much, i have an almost new OEM one, for fraction of the price!

drivetolive · 07-27-2010, 02:34 AM

So getting an OEM one would surely fix it? Or do you guys think my engine temp is getting too high causing the clutch fan to come on? B/c whenever I get off the highway I notice that it's off when I accelerate from an off-ramp, but after a minute or 2 of city driving it comes on.

Hey eurostyle, thanks for the offer, if you don't mind PM me a price and I could probably drop by tomorrow

.

Thanks for the help guys, keep it coming.

drivetolive · 07-27-2010, 02:52 AM

BTW sorry, don't know what brand it is.

Dr. Flyview · 07-27-2010, 09:43 AM

The way I understood it, the actual engine fan doesen't change speeds. It's always spinning at a medium rate. That's why there's a mechanical clutch which doesn't allow it to spin up to the engine's revs (too tight), but also doesn't let it stop spinning (too loose).

There is ANOTHER electrical engine fan (auxiliary fan). This one has 3 speeds: off, low, and high. If you have a mechanical clutch fan (above), you should really only hear this come on at idle when there's little airflow into the rad. It is controlled by a temperature switch that goes into the radiator. Perhaps if this is the aftermarket one you're talking about, it's no longer connected to this switch, or doesn't correctly interpret the readings.

BTW you don't want a fan to be too fast or on when it's not supposed to be, since you may run the engine too cold.

drivetolive · 07-27-2010, 08:13 PM

Sorry forgot to mention (and I'm sure this makes a difference), when sitting idle at a red light for example, I can't hear the fan (obviously), it's only when I begin to accelerate I could hear the thing come on and get louder (it matches my engine rpms, the higher the rpms the louder the fan).

When my hood is open, I can feel and hear the fan blowing. Even if my engine is cold.

It only turns off after say 40 km/h.

drivetolive · 07-27-2010, 08:18 PM

Quote:

Originally Posted by Dr. Flyview

The way I understood it, the actual engine fan doesen't change speeds. It's always spinning at a medium rate. That's why there's a mechanical clutch which doesn't allow it to spin up to the engine's revs (too tight), but also doesn't let it stop spinning (too loose).

There is ANOTHER electrical engine fan (auxiliary fan). This one has 3 speeds: off, low, and high. If you have a mechanical clutch fan (above), you should really only hear this come on at idle when there's little airflow into the rad. It is controlled by a temperature switch that goes into the radiator. Perhaps if this is the aftermarket one you're talking about, it's no longer connected to this switch, or doesn't correctly interpret the readings.

BTW you don't want a fan to be too fast or on when it's not supposed to be, since you may run the engine too cold.

I think the manuals came with an electrical fan while the auto/step trannies came with the clutch fan (which is what I have).

Also, surprisingly, I don't think the engine takes any longer to warm up.

BTW, when the hood is open, I can hear and feel the fan on (blowing air). Revving the engine causes the fan to go faster too (increasing noise).

BTW Eurostyle, I will give you a call tomorrow, got busy today (I called you in the afternoon but wasn't able to after that).

Dr. Flyview · 07-27-2010, 08:51 PM

Unless the mechanical clutch fan is radically different on an e46 than and e36, it would never really "turn off". It maintains a constant grip. In your case, it's too tight, spinning with the engine rpms. I don't think you can hear it past 40km/h because of the wind noise...

drivetolive · 07-28-2010, 10:07 PM

Got the issue all sorted out. Turned out to be a defective OEM clutch fan. Thanks to Rocco for the help!

Thanks for the responses.