Clutch fan delete?

[rf900rkw]

Those dissin' seat heaters don't have bad backs. My heater is on more than not, year round.

[streetmaster56]

In 2008 we took our last vacation with all four kids before they started out on their own venture in life. We rented a house in Scottsdale and used that as a base to visit all the sites around. Went down town Phoenix and was filling up the car with gas, looked over at the bank sign and it said 113. Everyone says, but it's dry heat. I tell them, so is my kitchen oven! It is a beautiful place though.

Yeah man, im sure all the new undocumented residency, are enjoying it quite well, since it even hotter where they came from lol.

[Hoyt Clagwell]

Those dissin' seat heaters don't have bad backs. My heater is on more than not, year round.

Yeah, now only if the seats had "magic fingers" as well, I could get some real therapy while driving.

[Hoyt Clagwell]

Clutch fan removed. 10 minutes, slammed hood. Boy that feels good!

[Migou]

I put an electric fan on my car just in case the aux fan fails.

I used a 30” aluminum cake pan to mount the fan to the shroud. If I need access to the front of the engine, I disconnect the fan power wire and pull the shroud. Everything is out of the way.

[mpire]

Do you track your temp? I'm curious what you hit?

I live in Charlotte and I ditched my mechanical fan about a month ago. Temps are slowly getting hotter.

It was 82 today and I never got above 98.

Attachment 714282

I have water temp, engine coolant temp (in the block), differential temp, transmission temp, and I'm probably missing a few.

The mechanical fan does very little overall, and nothing when you are actually moving.

If you don't replace the plastic fan with a NEW fan, and a NEW fan clutch its a ticking time bomb. Plus the plastic has to be NEW, not new old stock.

I have put in electric fans and honestly it does very little because of the stock AC fan that kicks on with engine temps.

If you have anxiety, then get an electric fan, its not really that expensive or all that hard to install.

However, I would toss the 20+ year old plastic fan and fan clutch ASAP, what you do next is totally up to you.

[Tim95M3]

A lot of people treat this topic like discussing religion or politics on Christmas. All I know is that I've removed the fans from my M52B28 and M52TUB28 and closed the hood with no issues. Even crossing through the desert and stopping at the Hoover Dam in 118F weather.

[Ahwahnee]

Clutch fan removed. 10 minutes, slammed hood. Boy that feels good!

I just acquired a 98 M Roadster and y'all have convinced me to delete that sucker (pun intended).

I have the Bentley manual and it seems simple enough: 32mm LH nut and a couple of plastic rivets.

Is there an easy way to immobilize the pulley?

Anything else I need to know?

Many thanks for any advice.

[rf900rkw]

I have seen countless aftermarket fan failures. I have seen exactly one factory aux fan failure.

[Hoyt Clagwell]

I just acquired a 98 M Roadster and y'all have convinced me to delete that sucker (pun intended).

I have the Bentley manual and it seems simple enough: 32mm LH nut and a couple of plastic rivets.

Is there an easy way to immobilize the pulley?



Anything else I need to know?

Many thanks for any advice.

I had the special tool left over from changing my water pump.

[zellamay]

I just acquired a 98 M Roadster and y'all have convinced me to delete that sucker (pun intended).

I have the Bentley manual and it seems simple enough: 32mm LH nut and a couple of plastic rivets.

Is there an easy way to immobilize the pulley?

Anything else I need to know?

Many thanks for any advice.

Yes, what you need to know is that the "fan delete" does not work in the desert heat. Failed attempts by desert dwellers have been posted here many times. But if you stay in the higher altitudes of Mt. Lemon, you'll be okay. .... Every now and then, I think I can make it work. I've been playing with a dual 12" Spal fan setup in my head. Seems like it should work. Problem is, all my other attempts seemed like they should work also. They didn't. Having lived with the stock mechanical fan for years, I've come to think the "fan delete" mod is overrated. Yes, there is a little fan noise I don't like, but it works fine. I think that if one is worried about the old fan blowing up, get a new stock fan.

[Hoyt Clagwell]

. I think that if one is worried about the old fan blowing up, get a new stock fan.

Yes, but do you know if the "new stock fan" is really new or NOS. Also, how often should you replace it. 'not being smart or disagreeing, these are just some questions that I had.

[ProductUser]

Someone once asked me if I gamble. My answer, "Yes, when I eat out and with my plastic Z3 fan."

[BimmerBreaker]

I don't think the fan blades are the problem. It's either the clutch seizes and spins the fan way faster than its rated for, or more commonly, bad motor mounts cause it to hit the radiator and explode. New fan blades won't help in either case. The fan clutch can also fail in a way that it won't lock but that doesn't cause an explosion (newspaper test will test for this condition)

I don't think there is a one size fits all solution for the fan clutch delete. Many climates you are fine to remove the fan, that is true. But it's also well documented that in very hot and dry climates, with mixed driving (not just driving through the desert on the highway where a fan makes no difference anyways) it has been shown time and time again that a fan delete will cause temps to climb. Sometimes a lower temp fan switch prevents the runaway overheating if you are just barely overheating, but usually if it's hot enough to overheat in any condition it's only one really hot day from becoming *really* bad and just running the mech fan or electric puller is the best option.

FWIW if you do a fan clutch delete and your aux fan fails your car will still overheat at idle even in colder climates (possibly with the exception of those areas so cold you block the radiator off with cardboard to help it get to operating temp)

The fan clutch issue is imo a bit misunderstood and over hyped in the first place. I do think more often than not it's an issue when the motor mounts fail. They don't just explode randomly very often like a lot of people seem to think.

I have seen countless aftermarket fan failures. I have seen exactly one factory aux fan failure.

I've seen multiple OE aux fan failures. But I live in a hotter climate where the aux fan will get more use. But I've also sold aux fans to Z3 guys on the east coast who had fan failures. So it's not like the aux fan is bulletproof, failure does happen

Aftermarket fans fail too but my recommendation is to keep the stock aux fan in place and run an aftermarket puller fan... That way you still have two fans, but the clutch fan is eliminated

[IndianaRoadster]

Aftermarket fans fail too but my recommendation is to keep the stock aux fan in place and run an aftermarket puller fan... That way you still have two fans, but the clutch fan is eliminated

This is what I did and am very pleased. I did have a second temp switch bung installed, being that it was a custom made radiator. The auxiliary fan runs off of the original and the new electric fan has it's own temp switch. So one system could totally fail, and I would still get home.

[zellamay]

I don't think the fan blades are the problem. It's either the clutch seizes and spins the fan way faster than its rated for, or more commonly, bad motor mounts cause it to hit the radiator and explode. New fan blades won't help in either case. The fan clutch can also fail in a way that it won't lock but that doesn't cause an explosion (newspaper test will test for this condition)

I don't think there is a one size fits all solution for the fan clutch delete. Many climates you are fine to remove the fan, that is true. But it's also well documented that in very hot and dry climates, with mixed driving (not just driving through the desert on the highway where a fan makes no difference anyways) it has been shown time and time again that a fan delete will cause temps to climb. Sometimes a lower temp fan switch prevents the runaway overheating if you are just barely overheating, but usually if it's hot enough to overheat in any condition it's only one really hot day from becoming *really* bad and just running the mech fan or electric puller is the best option.

FWIW if you do a fan clutch delete and your aux fan fails your car will still overheat at idle even in colder climates (possibly with the exception of those areas so cold you block the radiator off with cardboard to help it get to operating temp)

The fan clutch issue is imo a bit misunderstood and over hyped in the first place. I do think more often than not it's an issue when the motor mounts fail. They don't just explode randomly very often like a lot of people seem to think.



I've seen multiple OE aux fan failures. But I live in a hotter climate where the aux fan will get more use. But I've also sold aux fans to Z3 guys on the east coast who had fan failures. So it's not like the aux fan is bulletproof, failure does happen

Aftermarket fans fail too but my recommendation is to keep the stock aux fan in place and run an aftermarket puller fan... That way you still have two fans, but the clutch fan is eliminated

Thanks for clarifying. I have one disagreement by experience: You say " not just driving through the desert on the highway where a fan makes no difference anyways" ... In my best setup, (which I've detailed in the past, so won't reiterate here) at 110+ ambient, I could get my Z3M to stay cool enough at a stoplight, and on the highway up to about 80 mph. At 90+, the temp gage would move. I don't know why. If I did, I might have been successful. EDIT: forgot to mention: I put the stock mech fan back on, problem solved.

[rf900rkw]

There is something about the S52 airflow that causes the flow through the radiator to stall at high road speeds, higher than legal. I never did figure out if this was a function of piss-poor ducting, or just weird effects of the 4cyl based bumper/grille and the M aerodynamics. This issue does not effect the non M cars at all, nor the S54 cars which have much more elaborate air control in the engine bay.. the fact that putting the mechanical fan back on fixes it leads me to believe that enough air to keep the engine bay pressurized is finding a way around the radiator rather than through it. I reducted mine with proper sealing and a good design for the bellypan. Problem solved.

Again, this is an S52 issue only. The M52TU/M54 cars were I say remove and slam do not show this perversity.

On the rarity. Zfest State College, two fan explosions during the event, a third on the way home. All caused by seized fan clutches, non via engine mount failure. None reporting a massive noise *before* (not during) failure. Fans hitting the shroud was a common thing, Chevy, Jaguar, Volvo, yada yada. In every case they make a HORRENDOUS noise without damage, not a silent explosion.

In the case of a electric fan failure, the heater by itself is enough fan/cooling to control the temps, even during the summer. Zero chance of issues in winter.

The Aux fan is on any time the AC is on. That is year round here, more for dehumidifying.

[Ahwahnee]

Thanks for the insight and opposing views. It seems like every auto forum develops a few of what I call 'boxers vs briefs' topics, i.e. no single definitive answer.

I do drive in one of the hottest cities on the planet (Tucson) and so I am wary of giving up any part of the original cooling system.

Has anyone here ever considered adding a metal shield to the top of the shroud (like on a big Healey) for some hood protection should that factory IED decide to let go?

[BimmerBreaker]

I'm in Phoenix, so even a bit hotter than Tucson... I agree with not wanting to mess with the cooling system but imo adding an electric fan is a reasonable compromise, but keeping the fan clutch is certainly a tad easier. No reason you can't put some metal at the top of the shroud, but any piece thick enough to deflect the fan might require some finesse to fit under the hood. It's a fairly tight fit in that area


Perhaps there is something about humid environments that cause fan clutches to seize more often and perhaps due to the hot climate I live in, rubber dries out faster and I see more failures related to mount failure. I just simply don't think it's a one size fits all solution.

[streetmaster56]

I don't think the fan blades are the problem. It's either the clutch seizes and spins the fan way faster than its rated for, or more commonly, bad motor mounts cause it to hit the radiator and explode. New fan blades won't help in either case. The fan clutch can also fail in a way that it won't lock but that doesn't cause an explosion (newspaper test will test for this condition)

I don't think there is a one size fits all solution for the fan clutch delete. Many climates you are fine to remove the fan, that is true. But it's also well documented that in very hot and dry climates, with mixed driving (not just driving through the desert on the highway where a fan makes no difference anyways) it has been shown time and time again that a fan delete will cause temps to climb. Sometimes a lower temp fan switch prevents the runaway overheating if you are just barely overheating, but usually if it's hot enough to overheat in any condition it's only one really hot day from becoming *really* bad and just running the mech fan or electric puller is the best option.

FWIW if you do a fan clutch delete and your aux fan fails your car will still overheat at idle even in colder climates (possibly with the exception of those areas so cold you block the radiator off with cardboard to help it get to operating temp)

The fan clutch issue is imo a bit misunderstood and over hyped in the first place. I do think more often than not it's an issue when the motor mounts fail. They don't just explode randomly very often like a lot of people seem to think.



I've seen multiple OE aux fan failures. But I live in a hotter climate where the aux fan will get more use. But I've also sold aux fans to Z3 guys on the east coast who had fan failures. So it's not like the aux fan is bulletproof, failure does happen

Aftermarket fans fail too but my recommendation is to keep the stock aux fan in place and run an aftermarket puller fan... That way you still have two fans, but the clutch fan is eliminated

Welp as far as the motor mount go, those where replaced with new M3 mounts, so i know im good in the reguard. But decided to reinstall the clutch fan for now, until i figure out either on an electric fan replacement or just go with the pusher fan only. But i took the roady out for a state inspection, and the temp gauge was in its usual spot. Guess i can deal with sounding like a school bus for a little while longer lol.

[CoconutPete]

I can't explain why, but this whole thing has me wanting to install 2 LED's somewhere, one to indicate that the aux fan is running on low and one to indicate it's running on high? Why you ask? I think it would be fun!

[rf900rkw]

It's not unusual to see a car with the engine mounts so sagged that the oil pan is beating on the X-brace. Even then the fan clears.

[zellamay]

There is something about the S52 airflow that causes the flow through the radiator to stall at high road speeds, higher than legal. I never did figure out if this was a function of piss-poor ducting, or just weird effects of the 4cyl based bumper/grille and the M aerodynamics. This issue does not effect the non M cars at all, nor the S54 cars which have much more elaborate air control in the engine bay.. the fact that putting the mechanical fan back on fixes it leads me to believe that enough air to keep the engine bay pressurized is finding a way around the radiator rather than through it. I reducted mine with proper sealing and a good design for the bellypan. Problem solved.
Again, this is an S52 issue only. The M52TU/M54 cars were I say remove and slam do not show this perversity.

Not being willing to let a dead horse just lie there in peace, I have been re-thinking the problem of fan-delete on my S52 M Roadster.
Maybe it's because I've added a pretty good oil cooler, and see that it lowers oil temps around 10F at 85 ambient. That's a huge cooler that I didn't have when I tried fan-delete before.
Also, following Randy's advice, I've closed off a lot of air that could have been going around the radiator into the engine bay.
I'm not sure where my bellypan should end: at the radiator, (where it is now), or further back, closer to the engine.

My problem was highway speeds.
With an electric puller fan, I could control idle temps, but at 110+ ambient, 80+ mph, the temp gauge would start to rise.
I could relieve it by reducing to 55 mph.

So, here is my question:
Is it possible that the aftermarket puller electric fan, when running, actually impedes airflow through the radiator at 85 mph?

I tried some internet searches, didn't come up with solid facts, but it seems possible.
I read one example of hot-rod guys taking the electric fans off to reduce highway temps, but at this point that's just a story.

[sleeperz]

Did Randy W. ever share his reducting work on here? Just wondering, because I have some of that on my to do list for my S52.

[Ahwahnee]

...No reason you can't put some metal at the top of the shroud, but any piece thick enough to deflect the fan might require some finesse to fit under the hood. It's a fairly tight fit in that area...

I'm trying a piece of ¼" neoprene across the top. I think it would stop plastic shrapnel should the worst happen and so far seems to tolerate engine heat (though we've only had a couple of 90⁰ days).

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