Fan Question... Fan Runs Continuously

SS3/4/5 · Sun, Nov-14-2010, 10:17:24 PM

I've only had my car about 3k miles, so I'm new to these. My question is about the fan behind the radiator, the one that runs off the engine, NOT the one you can see through the kidneys. This is the "clutch fan" right??? I just had a half cooling system overhaul done, I replaced the belts, thermostat, fan clutch, etc. I basically replaced everything except the radiator and expansion tank.

Before I had this work done this fan that runs off the belts would run every once in a while, when stopped or going slow etc. but not all the time as far as I can recall because if I remember correctly you can feel it kick on. Well I've had this work done and now it runs all the time continuously, it runs the second I start the car cold and it is running when I pull off the highway and pop my hood on the off ramp.

Is this normal or is something up? Should this fan be running the whole time?

Oh and I searched and it seems the common problem is opposite of mine, fans that don't run.

Thanks.

kingchris · Sun, Nov-14-2010, 11:05:28 PM

SS3/4/5 · Mon, Nov-15-2010, 12:11:43 AM

Quote:

Originally Posted by kingchris

I'm looking around too...

SS3/4/5 · Mon, Nov-15-2010, 12:50:39 AM

Damn, nobody knows if this fan is supposed to be running the entire time?

ClarkeBurns · Mon, Nov-15-2010, 01:01:04 AM

Dude it's a mechanical fan. It's tied to the engine, so it's gonna run when the engine's on. The one you hear cycling is the aux (electrical) fan, which goes off a temperature sensor in the side of the radiator.

SS3/4/5 · Mon, Nov-15-2010, 01:29:14 AM

Dude thanks, so when it didn't run continuously before that was a symptom of the clutch needing replaced?

Why is there a clutch on it if it's supposed to spin continuously?

kingchris · Mon, Nov-15-2010, 02:00:13 AM

The clutch is on there so that when the engine revs high, the fan won't spin as fast. Think about the potential horsepower you rob if it was direct drive and the damage it could cause if it broke apart.

Your clutch before was bad hence the fan may not have spun when the engine is idling as it is designed to do.

SS3/4/5 · Mon, Nov-15-2010, 02:41:26 AM

Thanks King.

ClarkeBurns · Mon, Nov-15-2010, 02:44:02 AM

OP--I'd recommend removing your mechanical fan. You can replace it with a spal electric fan or just leave it off. If you add stuff called "water wetter" to your coolant, add a lower temp thermostat, and get a switch to turn on your aux fan earlier, you'll be good to go. Understeer.com sells a kit; it's easy to do.

Sun, Nov-14-2010, 10:17:24 PM	#1
SS3/4/5 Registered User Join Date: Nov 2010 Posts: 67 Reputation: 0 Location: Sonoma County	Fan Question... Fan Runs Continuously I've only had my car about 3k miles, so I'm new to these. My question is about the fan behind the radiator, the one that runs off the engine, NOT the one you can see through the kidneys. This is the "clutch fan" right??? I just had a half cooling system overhaul done, I replaced the belts, thermostat, fan clutch, etc. I basically replaced everything except the radiator and expansion tank. Before I had this work done this fan that runs off the belts would run every once in a while, when stopped or going slow etc. but not all the time as far as I can recall because if I remember correctly you can feel it kick on. Well I've had this work done and now it runs all the time continuously, it runs the second I start the car cold and it is running when I pull off the highway and pop my hood on the off ramp. Is this normal or is something up? Should this fan be running the whole time? Oh and I searched and it seems the common problem is opposite of mine, fans that don't run. Thanks.

Sun, Nov-14-2010, 11:05:28 PM	#2
kingchris Registered User Join Date: Apr 2009 Posts: 253 In the garage: '98 BMW M3 Reputation: 0 Location: DFW	__________________ 98 BMW M3: Cosmos Black w/Magma int. 87 Buick Grand National: Black w/Grey int.

Mon, Nov-15-2010, 01:01:04 AM	#5
ClarkeBurns At the limit of lateral adhesion Join Date: Sep 2008 Age: 26 Posts: 1,036 Reputation: 0 Location: Colorado Springs	Dude it's a mechanical fan. It's tied to the engine, so it's gonna run when the engine's on. The one you hear cycling is the aux (electrical) fan, which goes off a temperature sensor in the side of the radiator. __________________ Previous: 1995 Avus M3 2004 Mystic M3 Current: 1999 Hellrot M3 (80k miles) Looking to buy: OEM high arch spoiler in Hellrot (or whole trunklid) Would consider a GT style wing as well (w/o risers). Zionsville competition cooling kit, Samco hoses, Stewart WP, clears + black kidneys, AA Gen III muffler, X-brace, Sparco front strut tower brace, H&R front sway, oil pump nut secured, ZKW headlights, Motion Motorsports underpanel, V1 hardwire, 17x9 LTW5s in 245/40 Michelin Pilot Super Sports all around, AST4100s with 550F/650R, Vorshlag camber plates, Brembo drilled rotors, PF pads. More to follow.

Mon, Nov-15-2010, 01:29:14 AM	#6
SS3/4/5 Registered User Join Date: Nov 2010 Posts: 67 Reputation: 0 Location: Sonoma County	Dude thanks, so when it didn't run continuously before that was a symptom of the clutch needing replaced? Why is there a clutch on it if it's supposed to spin continuously? Last edited by SS3/4/5; Mon, Nov-15-2010 at 01:34:02 AM.

Mon, Nov-15-2010, 02:00:13 AM	#7
kingchris Registered User Join Date: Apr 2009 Posts: 253 In the garage: '98 BMW M3 Reputation: 0 Location: DFW	The clutch is on there so that when the engine revs high, the fan won't spin as fast. Think about the potential horsepower you rob if it was direct drive and the damage it could cause if it broke apart. Your clutch before was bad hence the fan may not have spun when the engine is idling as it is designed to do. __________________ 98 BMW M3: Cosmos Black w/Magma int. 87 Buick Grand National: Black w/Grey int.

Mon, Nov-15-2010, 12:50:39 AM	#4
SS3/4/5 Registered User Join Date: Nov 2010 Posts: 67 Reputation: 0 Location: Sonoma County	Damn, nobody knows if this fan is supposed to be running the entire time?

Mon, Nov-15-2010, 02:41:26 AM	#8
SS3/4/5 Registered User Join Date: Nov 2010 Posts: 67 Reputation: 0 Location: Sonoma County	Thanks King.

Mon, Nov-15-2010, 02:44:02 AM	#9
ClarkeBurns At the limit of lateral adhesion Join Date: Sep 2008 Age: 26 Posts: 1,036 Reputation: 0 Location: Colorado Springs	OP--I'd recommend removing your mechanical fan. You can replace it with a spal electric fan or just leave it off. If you add stuff called "water wetter" to your coolant, add a lower temp thermostat, and get a switch to turn on your aux fan earlier, you'll be good to go. Understeer.com sells a kit; it's easy to do. __________________ Previous: 1995 Avus M3 2004 Mystic M3 Current: 1999 Hellrot M3 (80k miles) Looking to buy: OEM high arch spoiler in Hellrot (or whole trunklid) Would consider a GT style wing as well (w/o risers). Zionsville competition cooling kit, Samco hoses, Stewart WP, clears + black kidneys, AA Gen III muffler, X-brace, Sparco front strut tower brace, H&R front sway, oil pump nut secured, ZKW headlights, Motion Motorsports underpanel, V1 hardwire, 17x9 LTW5s in 245/40 Michelin Pilot Super Sports all around, AST4100s with 550F/650R, Vorshlag camber plates, Brembo drilled rotors, PF pads. More to follow.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode