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  #1  
Old 06-01-2021, 04:45 PM
urquattrogus urquattrogus is offline
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Default Removing the Viscous Fan?

Has anyone done this?

A viscous fan was quite old fashioned even when the car was new? Also surprised the S54 has one too.

I have put a new fan clutch on mine just recently.

To some degree if it ain't broke, but I was just wondering...

However, the fan can be quite noisy and surely must add extra inertia to the engine as it's directly connected to the crankshaft.

I think there are supplementary electric fans? Its not uncommon to have one large electric fan and then afterun fans.

This then puts more load on the alternator and in term that takes some power to drive, but in general I was thinking a thermostatic electric fan might be more efficient?

Anyway, just got me thinking!
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Old 06-01-2021, 06:31 PM
Mad Max Mad Max is offline
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I removed my viscous back in 2014, before you do it though check that your AC fan works and fit the 88*C temp switch to the rad, the standard one is 95*C, it just gives you a bit more safety doing it.

The difference isn't night and day, but it is there. I only use my car in the summer and I've had no issues with oil or water temps, in fact my water temp always sits just to the left of centre.

Going back through my invoices the PN for the switch is 61.31.8.376.440.

Last edited by Mad Max; 06-01-2021 at 06:32 PM. Reason: Typo
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  #3  
Old 08-01-2021, 10:51 AM
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c_w c_w is offline
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As above, my car has not had a viscous fan on for years. A lower temp thermoswitch in the radiator itself will activate the from A/C "auxillary" fan at a more reasonable temperature (about 3/4 on the gauge), but this would only happen in hot summer days. If there is a concern just put the blowers on hot to drag heat off, but also as above the car really doesn't need that big fan hanging off the end.

Just FYI, the stock temp sensor leaves the aux fan off until it's nearly in the red! which is why many people think it's just for the A/C.

I actually put a manual switch on my car using a standard Z3 front/rear fog switch assembly (front fog will activate the fan on a simple circuit), so I can manually override and switch it on earlier or leave it to come on automatically.
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Old 08-01-2021, 11:06 AM
urquattrogus urquattrogus is offline
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Thanks, did either of you notice any difference to the way the engine revs?
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Old 08-01-2021, 06:29 PM
Mad Max Mad Max is offline
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Yes - you'll notice a little difference. If you combine it with an e46 M3 crank pulley, which is slightly smaller than stock, you'll notice it a little more.
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Old 09-01-2021, 01:50 PM
urquattrogus urquattrogus is offline
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Thanks, might try it out at some point. I have a new water pump to fit at some point as preventative maintenance so maybe when I’m replacing the coolant I might also try the lower temp switch and with/without the fan.
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  #7  
Old 10-01-2021, 07:16 PM
M1ke M1ke is offline
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Also removed Fan several years ago and fitted lower temp sensor - no issues experienced - also improves access to front of engine for belts / vanos.
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