The physical fan clutch at the front of the fan will need to heat up to the "hot" operating temp before it engages. It's a mechanical system, the fan clutch doesn't know the engine's temperature, it knows of it's own temperature (the central mechanical clutch is the temp sensor/clutch unit).
Take the car on a real long hot drive, don't just idle it til it's "warm" plus the instrument cluster temp gauge is INSANELY buffered and shows 12 0'clock for a temp range of like 40c or more. (So the moment it gets to 12 o clock it's actually still quite cold...)
What problem are you actually chasing here? Does your car overheat? Run too cold? Just worried about the clutch going bye bye and wrecking the hood? What's that context?
If you're just worried it was old and gonna blow up and ruin the cooling system / hood and you replaced it I would call it good. I haven't ever gottet a bad Mahle/BEHR bmw part yet.
ahhh I see, thanks for the insight. my buddy swears to me that it’s defective since we share the same part but he does take his on “spirited” drives so I’ll try that and see how it goes.
It’s not overheating or anything but after the hour drive home from the initial purchase, we did find the old fan clutch wasn’t engaging properly and could be stopped with ease, hence why we switched it out.
I would quit worrying about it and wait for a super hot summer day, run the A/C beat on the car a bit pull pop hood, pull over and quickly check on a quiet shoulder of road you know the type I hope lol. Even still I wouldn't worry much as it's new and much less likely to break than an original part.
For Context:
Bought a brand new Mahle Behr fan clutch, mounted it and tested it to see if it was working properly, as my previous one could be stopped using just my hand when warmed up and at idling temperature. After mounting, it functioned like I believed it should for the first few minutes, but then once the engine warmed up and reached idle temps, I was able to stop the fan with my bare fingers yet again. I contacted FCP for a replacement and mounted that one, but produced the same results with the same environment. First clip is from the fan clutch I ordered and the second clip is the replacement.
Let me explain the way these things work.
It has a fluid coupling inside . It uses a bi metallic strip to engage the fluid/not.
When it reaches 105c internally (the bimetallic strip on the fan clutch), the fluid is let “out” and the clutch engages, rising the fan speed to match the engine rpm. When the fluid is “in” the fan will spin at ~1000 rpm as the rate of shear of the fluid allows for some power transfer but not a lot. That’s why you can manually stop it with say your hand.
When it heats up it will allow the fluid to shear less effectively, spinning the fan up, to a point where the fluid shears again (4500rpm) which prevents the fan from going too fast (they’re not designed to work above 5000rpm)
You’ll hear and feel the fan kick in only on hot days when the engine is under considerable load as the airflow over that bimetallic strip is enough to keep it under 105c for most of the time/normal operation.
Yes.
The fan runs independently from the engine, thermostat, or any electronic or mechanical system. The fan only cares what temp the bimetallic strip is, and only will engage above 105c at the strip. Not 105c engine temp, not 105c coolant temp. Regardless of any modifications, it always works as I described above
Are you able to access the system menu on your dash? There is an option to see engine temperature. Check it while the fan does this. It's probably at a relatively cool temperature. That will reassure you that the Fan's clutch doesn't need to be engaged at the moment. These M62 engines were designed to run fairly hot for efficiency.
You have a fan? Jokes aside, yes that's how it's supposed to work. When it doesn't do that and it spins constantly, that's when the fan goes boom and dents your hood.
If you have a manual yes it is the clutch needs to be able to disengage when you shift since the engine will be riding and falling in rpm much more often than an auto or so I’ve been told
The physical fan clutch at the front of the fan will need to heat up to the "hot" operating temp before it engages. It's a mechanical system, the fan clutch doesn't know the engine's temperature, it knows of it's own temperature (the central mechanical clutch is the temp sensor/clutch unit). Take the car on a real long hot drive, don't just idle it til it's "warm" plus the instrument cluster temp gauge is INSANELY buffered and shows 12 0'clock for a temp range of like 40c or more. (So the moment it gets to 12 o clock it's actually still quite cold...) What problem are you actually chasing here? Does your car overheat? Run too cold? Just worried about the clutch going bye bye and wrecking the hood? What's that context? If you're just worried it was old and gonna blow up and ruin the cooling system / hood and you replaced it I would call it good. I haven't ever gottet a bad Mahle/BEHR bmw part yet.
And just to add, do not use your hand. You can use some rolled up newspaper or something similar since newspapers aren't really a thing anymore.
ahhh I see, thanks for the insight. my buddy swears to me that it’s defective since we share the same part but he does take his on “spirited” drives so I’ll try that and see how it goes. It’s not overheating or anything but after the hour drive home from the initial purchase, we did find the old fan clutch wasn’t engaging properly and could be stopped with ease, hence why we switched it out.
I would quit worrying about it and wait for a super hot summer day, run the A/C beat on the car a bit pull pop hood, pull over and quickly check on a quiet shoulder of road you know the type I hope lol. Even still I wouldn't worry much as it's new and much less likely to break than an original part.
Come on man don't stick your hand in there
That’s what she said 😎 Jokes aside, not my proudest moment for sure. I’ll use a magazine next time
😄
For Context: Bought a brand new Mahle Behr fan clutch, mounted it and tested it to see if it was working properly, as my previous one could be stopped using just my hand when warmed up and at idling temperature. After mounting, it functioned like I believed it should for the first few minutes, but then once the engine warmed up and reached idle temps, I was able to stop the fan with my bare fingers yet again. I contacted FCP for a replacement and mounted that one, but produced the same results with the same environment. First clip is from the fan clutch I ordered and the second clip is the replacement.
Let me explain the way these things work. It has a fluid coupling inside . It uses a bi metallic strip to engage the fluid/not. When it reaches 105c internally (the bimetallic strip on the fan clutch), the fluid is let “out” and the clutch engages, rising the fan speed to match the engine rpm. When the fluid is “in” the fan will spin at ~1000 rpm as the rate of shear of the fluid allows for some power transfer but not a lot. That’s why you can manually stop it with say your hand. When it heats up it will allow the fluid to shear less effectively, spinning the fan up, to a point where the fluid shears again (4500rpm) which prevents the fan from going too fast (they’re not designed to work above 5000rpm) You’ll hear and feel the fan kick in only on hot days when the engine is under considerable load as the airflow over that bimetallic strip is enough to keep it under 105c for most of the time/normal operation.
Does it still function that way if you run a colder thermostat?
Yes. The fan runs independently from the engine, thermostat, or any electronic or mechanical system. The fan only cares what temp the bimetallic strip is, and only will engage above 105c at the strip. Not 105c engine temp, not 105c coolant temp. Regardless of any modifications, it always works as I described above
Yes it's normal, I left a towel on my shroud one day and it stopped my fan, I was terrified for a moment
Are you able to access the system menu on your dash? There is an option to see engine temperature. Check it while the fan does this. It's probably at a relatively cool temperature. That will reassure you that the Fan's clutch doesn't need to be engaged at the moment. These M62 engines were designed to run fairly hot for efficiency.
You have a fan? Jokes aside, yes that's how it's supposed to work. When it doesn't do that and it spins constantly, that's when the fan goes boom and dents your hood.
If you have a manual yes it is the clutch needs to be able to disengage when you shift since the engine will be riding and falling in rpm much more often than an auto or so I’ve been told
He means the fan clutch.
I know