I dont know if its some rust thats keeping the clutch fan from bolting on this 1991 coupe I just got or what?



is there a difference between S4 and S5 clutch fans?

The s4 has 8 blades, and the s5 has 10 other than that, the flanges should bolt right up.

i cant seem to get the s4 one to seat right, like I said- the s5 car has some light rust around the center, dont know if thats keeping the fan from slipping on or not

they are different, the fan clutches are different

so that means I need a S5 fan, the car I bought had its fan missing!

just to piss you off!



new one is only $240.....and actually for them thats cheap!

I got someone who wants to sell me one for $22 shipped, sounds fair!

Is the clutch fan supposed to spin all the time? Are there times when the clutch is fully disengaged (not spinning)?

Sorry figured Someone would post by now...



When cold it should be fairly easly to turn but there should be a little resistance. Older ones do get loose. When it get's hot then it's supposed to engage the viscous fluid in the clutch...



Frankly I'd lose it and put an electric fan on.



I have a smaller used Flexilite off my car as I put in a honkin big one for the track car. Should be adequate for street use and moderate thrashing. You can order a sensor probe to automatically turn it on or put in a manual switch. Let me know if interested.



Stay cool! https://www.nopistons.com/forums/pub...#>/BURNOUT.gif

stock clutch fan works really good on a car that is running properly.

They should be the same I have a s5 on my s4, works great.

Frankly I would not. What good is a fan that taxes your electrical/charging system 30+ amps. Unless you buy an uber expensive one that draws very little current, you are then stuck with what shroud to you use.

I've heard that concern before and must admit I am not educated enough to say which one robs the most engine power, when operating. Perhaps an engineer type can tell us. I do know that many hotter applications have chose electric. If all the rest of your ducting, splash sheild are in place, forward motion in most cases is enough to keep these cool. I'ts stop and go where I see the most heat and then I like my 2500 cfm kicking in! When racing, most the time it will be off so no power robbing. When slowed down, ie: safety car, I am happy to lose some draw to keep it from boiling until they let us loose again. Mine is also hooked direct so it will still stay on with ignition off to help cool it all down.



I have admitadly hacked some foam and jammed into place to close the seals around my oversized radiator for now, (some locals have seen it.). I do plan to get the metal tape for sealing in the future. My fan and shroud are so big there is no needfor a shroud behind, tho it would ad a little more efficiancy, haven't seen the need yet.



This is backyarder, old timer sports car work by me and in NO WAY, is a reccomendation by a dealer. Just the choice I have made, from experience with fan clutch issues on other cars as well.



Neil

i have this fan

http://store.summitracing.com/partdetail.a...mp;autoview=sku

it pulls less than half of 30 amps previously mentioned and it works great. a friend uses the same one on a 300+whp 1st gen with no problems... price is right as well....



if you feel you need more cooling power for your 400whp setup or whatever check this fan out... from some short reasearch it's the best bang for buck in fan/shroud setups i found...

http://store.summitracing.com/partdetail.a...mp;autoview=sku

The fans will bolt up to either s4 or s5 but:



1. The fans have a different offset. If you try to put an s4 fan to a s5 fan clutch, the blades will hit the belts. MIght get aways with it with some washers.



2. If you try to put a s4 clutch on a s5 water pump it will not go in. The center hole in the s4 fan clucth is smaller and would have to enlarge.



3. There is probably a few more things but I haven' spent time trying to see what other things doen't work.



4. I went the electric fan way and that didn't work well. I think if you don' thave good ducking or a good shroud for that fan it doen't work well at highway speed.

I went back and bought a s5 clutch but i'm considering again the electric fan and doing some duct work.