Viscous clutch fan delete ?

[streetmaster]

Got a ? about doing an electric fan conversion on my 99 Z3 roadster 2.3, in the process of a cooling system overhaul, also wouldnt mind chucking the noisy wind tunnel sounding clutch fan, which i believe is rated at 2300cfm, im just curious which electric fan other members are using, did some searching, and mostly get (does not fit the Z3), im guessing because of the thickness of the fan assembly. Not sure if it matters, but I did do the M54B25 intake swap, along with new water piping under the manifold, just not sure what cfm to go with on the conversion.

[JLyons85]

I can't speak to everyone else's experience, but I just removed mine. Haven't noticed a blip on the coolant temp. My engine is the m52b28/m52tu, the fan that was on my car was new looking, but I was getting a loud clicking noise that I couldn't identify and I realized that it was the fan hitting the front of the VANOS unit. I assume that someone installed the wrong fan.

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[ptony101]

I have the same engine, M54B25, and I just took the mechanical fan out. Didn't add an additional electric fan. Admittedly, I haven't run through all temperature extremes yet but I don't see any change in water temp (and I reprogrammed my gauge to be more sensitive).

[jclausen]

The fan clutch is there for a reason, I would recommend either complete your fan conversion or put the fan clutch back on until you do, I mean it's only your coolant system. When the electric aux fan wears out you will be on the side of the road, hopefully not over heated.

[zellamay]

Here are some relevant threads: https://www.bimmerforums.com/forum/s...ht=temp+switch ... https://www.bimmerforums.com/forum/s...S52-fan-delete ... https://www.bimmerforums.com/forum/s...7-1998-2-8L-Z3 ...

[BimmerBreaker]

The fan clutch is there for a reason, I would recommend either complete your fan conversion or put the fan clutch back on until you do, I mean it's only your coolant system. When the electric aux fan wears out you will be on the side of the road, hopefully not over heated.

The clutch fan is a backup as BMW was switching from mechanical to electric fans in these years. Later BMWs only have the sole electric fan

Usually is is recommended to run a lower temp fan switch with the mech fan delete

[JLyons85]

My e83 only has an electric fan

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[me77]

If I remember correctly, the ideal setup for fan removal is to take the visco-fan out and replace the temperature switch in the radiator with the one from the 4-cylinder (lower switching temperature).

If you leave the visco-fan out and everything else stays stock, your coolant temperature will fluctuate more in the upper range. You'll rarely see it go above 97-99°C with the visco-fan installed, with the visco-fan removed it will go up to 105°C during the summer before the electric auxiliary fan kicks on and brings the temperature back down.

[DiqueTico]

If I remember correctly, the ideal setup for fan removal is to take the visco-fan out and replace the temperature switch in the radiator with the one from the 4-cylinder (lower switching temperature).

If you leave the visco-fan out and everything else stays stock, your coolant temperature will fluctuate more in the upper range. You'll rarely see it go above 97-99°C with the visco-fan installed, with the visco-fan removed it will go up to 105°C during the summer before the electric auxiliary fan kicks on and brings the temperature back down.

This is exactly what I experienced, and I read somewhere that the optimal operating temp is 190F so I went with the 16” slim Mishimoto fan kit and paired it with the radiator they sell and turned out perfect. The fan moves 1850cfm. I even wired a switch through the firewall (below the fusebox) so I can override the temperature probe if anything. Im pretty sure you can just buy the fan kit and itll mount right up to the radiator.


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[streetmaster]

Yeppers, I was looking at the Mishimoto 16" fan setup, I guess its a replacement for the clutch hub fan on the E36, but also said it wouldn't work on the Z3, apparently it does, wasn't sure for fear of it coming in contact with the water pump.

[DiqueTico]

It is very tight especially with the rad im running. You can measure it out with a caliper just to be sure it fits in your setup. Im also running power pulleys from turner, not sure if they are any slimmer than oem.


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[streetmaster]

Yeah man, i've replaced my pump, along with a new aluminum pulley, and the stock rad, by chance do you recall about how far the fan hub is from the mounting point of the rad, hopefully its around 2.5" considering you're new rad is either thinner or thicker than oem. Im sure ill be golden, yeah that fan drag of the clutch fan drove me nuts lol.

[bdiefAZ]

Would this "2 for 1" fan swap apply to the Z3?

http://www.zhpmafia.com/forums/showt...)-doityourself

https://e46fanatics.com/forum/showth...9735&highlight

[BimmerBreaker]

Would this "2 for 1" fan swap apply to the Z3?

http://www.zhpmafia.com/forums/showt...)-doityourself

https://e46fanatics.com/forum/showth...9735&highlight

Dont think so and those electric fans wont fit the z3 properly either. Did some research on that recently myself...

[Tigershark48]

Just got my M Roadster and will be deleting clutching fan first chance I get. Will be logging water temps on each outing through the 2019 summer season. My typical treks will be 75-100 miles each. If it behaves through hot weather (Wisconsin 90s F), I’ll leave it with fan delete only. I will not be commuting or in stop and go traffic, so I’m confident it will be fine. Will post results around this time next year. Both my motorcycle and roadster are not looking forward to winter storage. :-(((

[BimmerBreaker]

Fan deletes seem fine until about 95-100+ degree weather only with extremely low humidity. Any other situation the cars are fine as-is without em. Lower temp fan switch helps too.

[Tigershark48]

Viscous clutch fan removal done. I had a big old 1 3/16” open end (slightly too big, but worked) that broke it loose easily. Tight removal space, but finessed it out. Removal only with no other changes with optional fans, thermostat, etc.

We’ll see what future water temps do. Should be fine and don’t have to worry about exploding part damage. The mileage is low at 20k, but it’s still 20 years old. I don’t know what internal deterioration is possible, but I’d rather not take that chance. It also sounds better with a dominate exhaust rumble versus hoover vacuum cleaner sound under the hood.

[bdiefAZ]

Is the electric cooling fan on the M54 powered Z3 controlled by the ECM or via thermal sensor on the radiator?

[BimmerBreaker]

Is the electric cooling fan on the M54 powered Z3 controlled by the ECM or via thermal sensor on the radiator?

Thermal switch, they did not switch to the DME controlled PWM system on Z3's

[deni2s]

Spal VA08-AP51/C-23A fits properly. There was one more Spal model a bit thicker (I think by ~20mm) and quieter which probably should fit as well.

Thermal switch, they did not switch to the DME controlled PWM system on Z3's

M44 (or M43 don't remember exactly which) thermal switch signal for sure is going through DME. I know that because I helped someone diagnose problem, we found out that DME was the culprit (and I have no idea why it has to go through DME there).

[bdiefAZ]

Thermal switch, they did not switch to the DME controlled PWM system on Z3's

Does that apply to the M54 cars?

[BimmerBreaker]

Spal VA08-AP51/C-23A fits properly. There was one more Spal model a bit thicker (I think by ~20mm) and quieter which probably should fit as well.




M44 (or M43 don't remember exactly which) thermal switch signal for sure is going through DME. I know that because I helped someone diagnose problem, we found out that DME was the culprit (and I have no idea why it has to go through DME there).

Yes but E39 M54 cars for instance dont have that radiator mounted thermal switch they use DME magic coupled with temp at thermostat and other stuff to determine if fan works and at what particular variable speed.
Z3s never got the PWM fan setup, all Z3s have rad mounted temp sensors and use them for coolant fan trigger points is what I was saying.

Does that apply to the M54 cars?

Yes... I was replying to a post about you asking about M54s

ALL Z3s regardless of engine operate like that

[bdiefAZ]

Another question:

The aux fan on the Z3 is triggered either by the AC system running or a temperature switch in the radiator and has 2 speeds. Would it be possible to run a larger fan as a puller (more efficient) with this dual purpose setup and use existing wiring from the aux fan? Is there something that I am missing?

Sorry for the repeated/re worded question, I am not the electrical expert!

[ProductUser]

Using the search feature will provide an immense amount of information surrounding the mechanical fan removal. This topic has been discussed at length and in great detail over the years.

[z3forlife]

Another question:

The aux fan on the Z3 is triggered either by the AC system running or a temperature switch in the radiator and has 2 speeds. Would it be possible to run a larger fan as a puller (more efficient) with this dual purpose setup and use existing wiring from the aux fan? Is there something that I am missing?

Sorry for the repeated/re worded question, I am not the electrical expert!

You would likely overload the circuit trying to run two fans in the same circuit. There is a thread that discusses adding a additional temp sensor in the return hose from the block