Switching to an electric cooling fan

[Bmachine]

My car is an all stock AC Auto '74. It still has the old 5 blade red fan. When I am stopped at a red light the temp gauge will climb about 3/4 of the way up and start to make me really nervous until that little guy gets to work and starts to sloooowly bring it back to 3 o'clock. And this is the winter!!! Not good for my nerves.

I did a lot of searching on the board and read about switching to the 9 blade viscous version but I remember switching to an electric fan in most of my Tiis and it was a fairly simple and very efficient operation.

After searching for "Electric fans" I read up on various options getting aftermarkets from Summit racing etc... but on this thread:

http://www.e9coupe.com/forum/showthread.php?t=17225

A few people were talking about using an e30 electric fan. I like the idea of staying within the family so I am very tempted by that. Only problem is, where do I hook up a temp sensor? My car is at CoupeKing now so I can't check but I read a post by HBChris who said that the Auto radiator does not have a place to screw in a temp sensor.

What would be the best option in this case?
And is there a shroud that would fit the e9 stock radiator with that fan?

Thank you very much.

Bo

PS: Since I have AC, I would need to use this fan as a puller. This would not be a problem with the e30 fan, would it?

 

[bdigel]

the e30 fan is a pusher and sits it the cowel in front of the condenser . alltough it could be done it would be a real pain in the rear to install , If it were me I would get one of the puller fans from someone like summit . find one of the install kits that have these things like zip ties that go though the Radiator to mount the fan .

they also sell kits that control the fan operation , mine is controlled by the ECU and an additional toggle switch

I believe Bimmer world also sells some of this stuff , but they wont have one in particular for an e9

 

[Nicad]

Because my rad is so thick now (triple core), I have gone with a Spal pusher. Looks to be well made. Hopefully will be making the mount in the next month.

 

[Bmachine]

Thanks very much bdigel and nicad. Great info.
I went ahead and ordered a 16" Spal puller.
I just need to figure out where to plug in a temp sensor since I don't believe my radiator has that option.
I got the impression that there was a way to plug it in the water pump maybe. (???). I'll need to check when I get my car back.

 

[HB Chris]

I think 74 was first year with temp sensor at bottom of rad with relay and control unit.

 

[Peter Coomaraswamy]

Hi Bo, which fan did you order and does it fit well? and cool well? Do you have any pictures?

Thanks

 

[Belgiumbarry]

i have my temperature sensors (to switch the fan ) in the thermostat housing on both cars ... works OK.... only they remain a fair time running after shut down. The sensor feels the engine rest warm coming up after shut down but no problem i think , extra cooling the radiator to create some thermic flow .

 

[Bmachine]

Hi Bo, which fan did you order and does it fit well? and cool well? Do you have any pictures?

Thanks

Ha! Funny you should ask Peter. This is one case where I decided to put my instincts aside and follow the recommendations of the more knowledgeable than me on this forum. And I returned the electric fan and instead ordered the later BMW model 9 blade fan with new coupling

02 Fan 9 blade D=420MM 1 09/1979 11521273086
03 FAN COUPLING 09/1979 11521260459

I still have not installed it since my motor is being built down in San Diego but it should happen in the next month or two. I hope.

My gut feeling is that I like the electric fan idea better. Seems cleaner, cheaper, easier to trouble shoot, less drain on the engine. I've done it on several of my Tii's and it always worked great. But I keep thinking there must be a reason why sfdon, HBChris, Peter Sliskovitch and Carl Nelson prefer the standard mechanical fan approach. That's a pretty solid combination of knowledge and experience to go against.

 

[Belgiumbarry]

sorry Bo , i think it has all and nothing less to do with OEM look....

 

[Peter Coomaraswamy]

sorry Bo , i think it has all and nothing less to do with OEM look....

I spoke to Don and he mentioned the "look as the only draw back". Any purist will look at my car and realize it's not "OEM", anyone who looks under the hood and doesn't have knowledge of the e9 won't know what they're looking at and so won't be able to tell, and anyone who knows it's not stock or necessarily "period correct" under the hood should say; "ok, cool, not going to win any concourse shows but probably drives well", so while I opted out on the hood-scoop, fuzzy dice, and spoilers I'm trying to make it a reliable, comfortable and hopefully quick little driver. My goal is to catch up to Andrew Wilson in the long rang trip and reliability category but I'm way behind at this point

 

[Bmachine]

sorry Bo , i think it has all and nothing less to do with OEM look....

I spoke to Don and he mentioned the "look as the only draw back".

Yes, I am sure that is correct.
I would also think that the electric fan also increases reliability. No strain on the water pump center bearing..., one less belt to deal with. Damn, apart from the look, it all sounds like a pretty solid case, doesn't it?

 

[JFENG]

Why can’t we squeeze in an electric fan in between the rad and condenser, and then modify the viscous coupling to essentially have nearly zero coupling. Your pretty red fan would still turn slowly yet drag and noise would be minimized when driving?

John

 

[JFENG]

And I find the sound of the OE fan annoying when moving away from a standstill. That whooshing sound detracts from the intake and exhaust noise.

 

[Peter Coomaraswamy]

Hi Bo, I'd love to have the part number and a recommendation for where to purchase the same fan as the one you returned. Thanks

 

[Bmachine]

Hi Bo, I'd love to have the part number and a recommendation for where to purchase the same fan as the one you returned. Thanks

Here you go Peter:
https://www.amazon.com/gp/product/B003PB9QRO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[twistinglane]

Is mechanical or electric is more likely to fail on the road? If electric failed without audible warning more of a risk?

 

[teahead]

Go both!

 

[mulberryworks]

My understanding is that the fans with the thin blades like the Spal produce more noise than ones with wider fan blades. Probably because of relatively increased cavitation from the smaller blades having to work harder. There may not be enough room behind the radiator for a thicker one, but certainly in front of the radiator or condenser, there is a lot of room.

 

[Belgiumbarry]

indeed , behind the radiator there's just enough space for a thin "Spal" type , even mounted as far to the left as possible. Also the best place because there the blown air has "free" room to exit and not restricted by the engine ....

@twistinglane ,
i think electric are quite reliable , and more : standing still you can hear them spinning , so there is a "warning" . Once driving , let's say above 20 mph , they have no use , wind by driving is already more than what they can produce.

 

[nyccsi]

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR1.TRC0