Electric fans and the Mechanical fan clutch (Aisin wins!!)

AliK

Vehicle Dating Officer
Staff member
Club Member
I’ve been meaning to add a pusher fan on the front of my rad for sometime now as I’ve had two viscous fans that never seem to come in well enough and with a half sized crank pulley on the ATi everything is running at half speed. This does make the temp gauge go further across than I like when idling on a hot day.

I have a circuit that reverses the fan direction after switch off (for 5 mins) to suck the hot air out of the engine bay and reduce heat soak.

I am about to send back the Aeroline fan I bought off eBay for c. £25 as it’s about £25 of build quality too!!! Be warned the blades were not balanced and not level - so the entire thing vibrated like mad vertically and horizontally!!!

I can’t imagine that would do the rad any good over time. Also, the motor / bearings are awfully noisy (not in a smooth way) and could be heard over the air whoosh! Based on what I saw, I would advise not bothering with the cheapo ones! I simply bought it as a cheap experiment but wouldn’t be happy to run it on the car. On the upside, the circuit works!

So the question is, has anyone else done what I’m proposing and even if not, what is your preferred electric fan?

I am tempted by the Mishimoto offering at around £60-£70. something like this ....
https://www.ebay.co.uk/itm/Mishimot...-/153077389098?_trksid=p2349624.m46890.l49286
 

Turn & Burn

Club Member
I see the MZR cars are running push fans, I think it’s a good idea for increasing engine bay space especially if ur running a crank sensor near the damper. Not sure on whether having it on the front blocks off some of the normal airflow cooling, I suspect it does so ur fan comes in a bit more often.
The Mishi fan looks identical to the cheap fans I’m using right down to fasteners and brackets, is the mishi just a rebadged unit (or is mine a copy). I’d look at SPAL if I was after good stuff.
 

jonbills

Membership Secretary
Site Administrator
I used to have electric fans, but swapped back the viscous fan because it doesn't have a fuse to blow. And looks right.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Thanks guys.

Interesting re. the Mishi fan - that was the reason I bought the Aeroline as it was identical to the more marked up branded ones! I had a look at SPAL but they don’t reverse direction by changing polarity :(

Jon - what brand of viscous coupling did you use? The 2 RockAuto ones I’ve had haven’t worked at the right temp - but they do a lot of brands and I don’t want to keep buying them, especially as their returns policy sucks!
 

Farmer42

Club Member
I tried an electric fan on mine a few years back when I bought a new radiator. It didn't do half as good a job as the viscous fan on both the coolant temp and the engine bay became really hot. The viscous fan does a good job at cooling the engine as well as the radiator. I went back to the viscous fan very quickly to stop overheating.

It's interesting to hear about the RockAuto couplings as I have also had issues with a couple that I have bought. They are both too stiff on cold temperature and it sounds like a Jet engine taking off. They are supposed to be quite freewheeling when cold and get stiffer so that the fan kicks in when hot. I went back to an old one and cleaned it up. It's not worth sending them back but not sure where to get a different make from.
 

Bazzateer

Club Member
Is sucking hot air out of the engine bay much more efficient than blowing cold air in?
I get the theory, just not sure how effective it is.
 

dav118118

Club Member
I’ve got both on my car. I think having an electric fan in front of the rad does restrict natural flow and can get a little hot when Idling in traffic on a hot day with just the viscous working. I have the electric fan wired to a toggle on/ off switch hidden under the dash and can turn it on whenever I need to. It does quickly cool temps down. I have it more as a fail safe should the viscous fan struggle on hot days stuck in traffic
 

toopy

Club Member
As a side note, i understand that heat wrapping the exhaust manifold can have a huge effect on heat soak in the engine bay, but no one seems to use it any more!
 

jonbills

Membership Secretary
Site Administrator
Thanks guys.

Interesting re. the Mishi fan - that was the reason I bought the Aeroline as it was identical to the more marked up branded ones! I had a look at SPAL but they don’t reverse direction by changing polarity :(

Jon - what brand of viscous coupling did you use? The 2 RockAuto ones I’ve had haven’t worked at the right temp - but they do a lot of brands and I don’t want to keep buying them, especially as their returns policy sucks!
This is the one I've got currently: https://www.rockauto.com/en/moreinfo.php?pk=1948188&cc=1209181&jsn=7
Couldn't tell you if it works at the right temp though. Just that it works.
 

Farmer42

Club Member
Just realised the mistake I made when ordering the fan clutch. There are 2 types - 1 that is standard so is basically fixed and engaged all the time and the other is thermal and gradually engages with increased temperature. I ordered the standard :banghead: which is probably why I am getting a constant whooshing sound even when cold. I think I will order the correct one and give it a try and hopefully it will be a bit quieter.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Just realised the mistake I made when ordering the fan clutch. There are 2 types - 1 that is standard so is basically fixed and engaged all the time and the other is thermal and gradually engages with increased temperature. I ordered the standard :banghead: which is probably why I am getting a constant whooshing sound even when cold. I think I will order the correct one and give it a try and hopefully it will be a bit quieter.

Do your temps ever make it to half way on the dial Paul? Incidentally, half way is pretty close to 90 degrees which my Audis religiously stick to.

Before you order, you’re welcome to try my current one in case it works better on your engine than it does on mine! Just ordered the Aisin so I should have it in a couple of weeks.
 

Farmer42

Club Member
Thanks Ali but yours won't fit. I had to change mine to a 280ZX fan and clutch to accommodate the 280ZX power steering drive. The 280ZX clutch has a longer shaft which clears the idler pulley for the P/S belt and it also has a bigger fan so keeps the engine bay a lot cooler. I bought a new clutch and have since reverted to an old one that Huw let me have but that is a bit noisy. I just ordered a GMB clutch from RockAuto which is a little more expensive but I made sure I read the blurb beforehand. Should be with me soon so I will let you know if it is any quieter and that the thermo part works ok. I do still have my 260Z fan and clutch which were fine but now won't fit.

My temp gauge gradually creeps up to 3/4 way on the gauge but takes ages - probably because the fan clutch is not working properly. When the thermostat opens, it then drops to 1/2 way and stays there even when it's boiling hot outside and I'm stuck in traffic (not that we have had lots of traffic for the last year!).

Incidentally, if you have a half size crank pulley should you not have changed out the other pulley wheels for a similar ratio so they turn at the same speed or faster? If the fan pulley is only going at half speed, that will also have an impact on your water pump and if your water pump is not spinning at the right speed the water is not circulating fast enough leading to higher temps and possible overheating. No new fan clutch will overcome that and I doubt that electric fans will solve it either.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Thanks Paul. I did manage to eventually source and lathe to fit a smaller pulley for the alternator, but there is no space for a smaller water pump pulley without connecting with the water pump housing!

I have a 160F thermostat which looks like it got in the way of a shot gun since I drilled it out a fair bit! ;)

the gauge sits around 1/4 to 1/3 cruising and in traffic on a hot day, it goes to 3/4 - but for the reasons we just discussed, I’d rather it didn’t and stayed closer to 1/2. Hence the plan for an electric fan for those hot day, long idling moments.
 

johnymd

Club Member
I'm sold on the factory fans. will never go back to electric but this is just my opinion and not based on any lab condition testing. I've sat in traffic for over 2 hours on a very hot day and temps never change. I also like the continuous airflow through the engine bay plus it's just a fit and forget solution. No more waiting for the fan to cut in.

My temp gauge on the various zeds always sits right in the middle and never moves. Not too cold and not too hot. The thermostat does all the work of keeping it just right.
 

Farmer42

Club Member
Thanks Paul. I did manage to eventually source and lathe to fit a smaller pulley for the alternator, but there is no space for a smaller water pump pulley without connecting with the water pump housing!

Ali, why don't you try a 280ZX clutch & fan with a smaller pulley wheel. The shaft on the 280ZX clutch is a little longer than a S30 and allows all the bolt on stuff to sit further out from the water pump housing. The other option is to fit longer bolts or studs and use a spacer. There should be enough room between the fan and radiator for either option - you only need about 10mm. I have a spare 280ZX clutch if you want to try it but you might have to order another cos its a bit noisy. At least you can see if it solves the distance issue before you invest in one. Having said that, if you have already ordered a new S30 clutch, I would go with the other option and use a spacer.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
I have had standard and electric fans. I like the standard fan but I've had blades crack and soften with heat and pull into the rad (holing it - you were there John) under extreme conditions. I then fitted a pusher fan and def noticed a small power increase. However the fan wasn't as efficient. I was doing trackdays so it was nice to be able to leave it running for a while after a session.

If you have a good standard fan and using your car on the road keep it. If you want more control over when the fan runs and need every bhp fit a big electric one. If you fit a pusher it's so much easier to turn the engine over with a spanner on the cranknut. Useful for tappet adjustment.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Thanks guys!

Paul, I would love to try out the 280zx viscous coupler as I hadn’t realised it has a longer shaft and may potentially solve my issue. I can always sell the Rockauto one if it doesn’t get used. I don’t understand how it would be possible to space the water pump pulley forward as it would be out of alignment with the alternator and crank pulleys, no?

Rob, I agree with your thinking. I want a pusher to run in tandem with my stock mech fan. What I like is the fact that the stock fan (barring falling to bits) won’t fail and if the belt snaps and I don’t realise, the pusher fan is still going to provide some cooling as well as addressing my worries about the temp gauge going further than I like.
 
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