Are viscous fans a joke

[Tom Galloway]

Generally I don't like any parasites sucking my power away but it's hot every day now. Plus, I adjust valves by turning the motor over with a wrench and the blades get in the way. Plus, the electric fan seems to do a good job. I test the viscous fan by - when warmed up - touching it with some rolled up paper to check its resistance, The original and 2 new fans all are easy to stop with the paper.

I have heard that the oil in the fan may leak out or, if stored laying flat the units can go bad.

Is it worth it to keep this parasite or just go electric?

[e30austin]

the factory opted to use a mechanical fan for a reason. if you have the capability of running one, i absolutely would. that being said, i generally replace fan clutches every couple of years. the quality of them is quite poor, along with most other parts, these days...

[nando]

the original mechanical fans are fine. I've never had a fan clutch fail, although obviously the originals do from time to time.

I had an electric fan only for a while. it maybe made a tiny difference, but I found the on-off cycles much more annoying than just running the mechanical fan, so I put it back on.

[varg]

I prefer an electric fan but I still have a mechanical fan on my E30 because I never bothered to find an e-fan that would flow enough with the AC on and the intercooler up front. The mechanical fan clutches are junk, but you may be finding that a lot of new parts are junk these days.. I bought a cheap one from FCP and it was bad out of the box, though I didn't install it for months after I had it. Instead of replacing it with a like item I just bought a more expensive one and ran it... Still have that almost new faulty one laying around. I didn't do the paper test I just drove it on a hot day and didn't like what I saw on the temp gauge.

[e30davie]

Id like to try one of these new speed controlled electric fans, with a proper controller that is temperature based to avoid those hard on/off fan situations. but im not convinced the added complexity outweighs the benefits. Mega squirt can probably control one quite nicely on a PWM output...I suspect alot of OEMs are using PWM controlled fans these days, so could probably get something pretty high quality from a junk yard.

On an old rwd corolla I removed the fixed engine fan (non hydraulic) and installed basic on/off temperature controller with the electric fan. It worked fine, and unless i was in stop start traffic it rarely turned on. but when it did it made a hell of a noise and even dimmed the headlights briefly as the alternator was tiny...

[gazellebeigem3]

keep it if you have ac. as for your valve adjustment concern; you can bump the starter via the diagnostic port. use a remote starter switch connected to the yellow black and the b+. I forget the pins but have at it: http://wedophones.com/BMWManualsLead.htm

[It's Soda Not Pop]

keep it if you have ac. as for your valve adjustment concern; you can bump the starter via the diagnostic port. use a remote starter switch connected to the yellow black and the b+. I forget the pins but have at it: http://wedophones.com/BMWManualsLead.htm

PIN 11 and 14

[Tom Galloway]

Thanks guys, I thought it was junk. Might be time to up the QC on after market stuff. And thanks again for the tip on valve adjustment.

[digger]

electric fan retrofits within available space on e30 just don't have the oomph of a properly running viscous one. The OE fans on newer BMW have way more guts

[McGyver]

keep it if you have ac. as for your valve adjustment concern; you can bump the starter via the diagnostic port. use a remote starter switch connected to the yellow black and the b+. I forget the pins but have at it: http://wedophones.com/BMWManualsLead.htm

Or make a remote starter trigger with the correct plug and never have to remember the pins again:

https://www.r3vlimited.com/board/forum/e30-technical-forums/e30-faq-and-diy/9969225-diy-making-a-remote-starter-trigger

[Panici]

Running a SPAL 30100401 tucked between the rad & intercooler.
Keeps the car cool all by itself on the street even with the M42 rad.

Had previously used a SPAL 30101517 which moves more air but was too thick for the intercooler to squeeze under the front valance.




On my E36 I ditched the clutch fan and just use the A/C aux fan.
No engine cooling issues, but the A/C also doesn't work.

[Northern]

^ I run the same as Panici on my turbo 24V between the IC and Z3M rad as well.
No issues in a northern climate, see a few 40deg (~105 in archaic British temperature increments) days a year here in the summer.

[ZEKTI]

With how hot some summers have been and sitting in standstill traffic I wired a simple 12” Spal pusher to the front of radiator. It's kept everything in check. A correct viscous fan does move a lot of air and a shroud is key.


Sent from my iPhone using Tapatalk Pro

[varg]

Good spal fan recommendation. Remember when choosing a fan that a cooling fan flow rating without a static pressure to flow relation curve is basically useless. Mishimoto or some other china rebrand where they just tell you "2400cfm!", can basically be outright discarded because at best you can assume it's a free air flow rate. Because there will be a pressure change across your core(s) the flow will be dramatically lower than free air and you have no idea how much since there's no published spec.

[Stanley Rockafella]

the original mechanical fans are fine. I've never had a fan clutch fail, although obviously the originals do from time to time.

My fan clutch is fine and keeps my engine at 11:30, even when idling in traffic.
The main problem was my rad. With that replaced, it's been running better than ever!