As part of my SLS rebuild attempt, I removed the viscus fan. And I did not reinstall it. Its winter up here and the electric fans will kick in at 110 just in case. It normally runs at 75 in town and 65 or so highway this time of year. And that did not change much since I only got to 80 in town.

Anyway, it may be physiological but it sure feels like the car has much better throttle response and a lot more kick.

I am not sure how much horsepower is produced at 1000 RPM, but it cant be much. And I would guess the fan sucks at least 20HP. Since the 20 or so HP wold be the same at 5000 RPM or 1000 RPM, I would suspect at low RPM its a great hinderance.

Anyone have some actual numbers? After a trip out of town I feel safe running without the fan for the winter. Two reasons, faster heat up and I think my viscus fan is faulty. I can not hold the fan at idle like I can in other cars, its seems like the clutch is mostly engaged full-time, although if I rev it lots I can tell when it fully engages.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

Sacrilege here.

On a recent round trip (3000miles - 5000kilometres more) I removed the viscous fan and installed an overide switch for the low speed on the auxillary fans.
Switch only applied when required in heavy traffic with AC on.

Seat of the pants tells me that I potentially saved a mile per gallon or so.
I carried the tools and the fan with me so I could replace it if required.

Removing the fan will increase MPG, however I know of a couple of people who have done so on SL's and they found that at least in Texas, the electric fan could not keep up.

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With best regards

Al

Al, I dont run a fan on my 6.3 and it seems to run just fine. There is a lot more power too... as if it needs it..

Well I think I will leave it off until spring. I keep track of my milage. My best in town is usually about 14mpg. Highway I have gotten up to 18 during summer, but as of late its usually between 15 and 16. I would LOVE to see a number around 20 highway and 16 in town.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

I took mine off my diesel and added a 16" electric fan.I rarely use it.Made it more stronger.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Ron, you run an electric fan on the 6.3? That's pretty impressive, what size / CFM are you running with?

I'd like to have this option on all of my cars, especially the 500SL as it struggles in the summer. The 6.9 did also but I have since sold it.

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With best regards

Al

When I had a Lincoln Mark VIII I learned a bit about electric fans. The Mark VIII fan was a popular install in other vehicles for its high CFM. Maybe I will pick up one used. Its a single fan design but should fit no problem in my 560. Its also a two speed, I may have to figure out something for that. But I bet others already have. At least it is designed to install on the back of the radiator, so I can keep the stock electric in place also.

I admit I like the roar of the viscus fan, but like I said I think mine is locked up near full-time.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

I'd love to put an elec fan on my 603 but I just don't think there's space The new plastic fan and clutch seem to do ok, and it never roars (though it does move a lot of air on startup / when it's hot out).

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Hi guys,my 87 190e 2.6 autos fan clutch been out for as long as i can remember and recently like yesterday i was trying to locate a front engine oil leak an decided to remove the fan and clutch assy as it was doin nothing for the cooling system.is there anyway i can do a repair to the clutch assy for it to be effective again or it needs to be replaced.thanks.

You may have a thermostat problem as your car seems to be running cold. You'll improve your fuel consumption if it runs at 90C as it should.

RayH

Funny you should mention this. I was thinking the same. At idle I did hit the magic mark to get the fans to fire up.

But without the fan I would expect some change. The change was so little I was thinking the t-stat may have been stuck open all along. And my economy has never been as good as I think it can be.

I think I will replace it just to be safe. Can I assume the location is front on top. There appears to be a t-stat housing between the dist and cruise actuator. It also appears to have some silver colored caulk around the base. Do I need some gasket in a tube or are there regular gaskets used for this? Just want to make sure I have all the right stuff before starting.

Thanks.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

When running a Electric fan, Wont the increased electrical load on the alternator cancel any hp savings?

I dont think so. The viscus fan wants to run at all times, even when not needed there is a drag on the engine. With electric, that drag will ONLY be when the fan runs. And I think the drag caused by the alternator will be less than the direct mechanical drag of the viscus fan.

I would LOVE to get dyno results, but I am not spending a couple hundred just to find out.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car