Torquatrol fan clutch test
#1
08-12-2018, 01:26 PM
Torquatrol fan clutch test
Hi
is there a way to test if the mechanical fan clutch works properly ?
Should it follow the drive 100% when warm, or is some slip allowed ?
The ROM and Haynes does just tell how to remove and fit the clutch...
i see some coolant temp rise when driving slowly in high ambient temperature. Temperature indication is fine at normal and high speed, so I guess my fan clutch could be causing this.
is there a way to test if the mechanical fan clutch works properly ?
Should it follow the drive 100% when warm, or is some slip allowed ?
The ROM and Haynes does just tell how to remove and fit the clutch...
i see some coolant temp rise when driving slowly in high ambient temperature. Temperature indication is fine at normal and high speed, so I guess my fan clutch could be causing this.
#2
08-12-2018, 02:18 PM
Veteran Member
It shouldn't be rock hard but also not loose as if it was on a ball bearing. If it spins freely, the clutch is dead. If it doesn't spin at all, it is dead. It should spin with resistance when cold.
You can also remove it and warm with a heat gun the center (a little coil) up and then spin it. If it works, it will become very stiff. When it cools again, it should turn free'er.
You can also remove it and warm with a heat gun the center (a little coil) up and then spin it. If it works, it will become very stiff. When it cools again, it should turn free'er.
Last edited by Daim; 08-12-2018 at 11:13 PM.
#3
08-12-2018, 02:38 PM
Veteran Member
My test is when the engine is cold and off, put a few fingers on the blade and turn the blade as hard as you can. Sort of a flick, but it's hard to describe. The blade should move about 1/3 to 1/2 of a turn. Any more and the clutch is weak.
As a further thought, is the radiator clean? Did you see the pictures a few days ago of the debris between the radiator and condensor? You can't see it until the radiator is removed, or at least the top rail is removed and the condensor and radiator can be moved apart a bit and you can look between them. The fan might be fine, but the radiator is blocked and not getting sufficient airflow.
Dirty rad pics here: https://www.jaguarforums.com/forum/x...g-warm-206092/
As a further thought, is the radiator clean? Did you see the pictures a few days ago of the debris between the radiator and condensor? You can't see it until the radiator is removed, or at least the top rail is removed and the condensor and radiator can be moved apart a bit and you can look between them. The fan might be fine, but the radiator is blocked and not getting sufficient airflow.
Dirty rad pics here: https://www.jaguarforums.com/forum/x...g-warm-206092/
Last edited by Jagboi64; 08-12-2018 at 02:41 PM.
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leo_denmark (08-12-2018)
#4
08-12-2018, 02:41 PM
#5
08-12-2018, 03:20 PM
My test is when the engine is cold and off, put a few fingers on the blade and turn the blade as hard as you can. Sort of a flick, but it's hard to describe. The blade should move about 1/3 to 1/2 of a turn. Any more and the clutch is weak.
As a further thought, is the radiator clean? Did you see the pictures a few days ago of the debris between the radiator and condensor? You can't see it until the radiator is removed, or at least the top rail is removed and the condensor and radiator can be moved apart a bit and you can look between them. The fan might be fine, but the radiator is blocked and not getting sufficient airflow.
Dirty rad pics here: https://www.jaguarforums.com/forum/x...g-warm-206092/
As a further thought, is the radiator clean? Did you see the pictures a few days ago of the debris between the radiator and condensor? You can't see it until the radiator is removed, or at least the top rail is removed and the condensor and radiator can be moved apart a bit and you can look between them. The fan might be fine, but the radiator is blocked and not getting sufficient airflow.
Dirty rad pics here: https://www.jaguarforums.com/forum/x...g-warm-206092/
I did not see this answer before I posted my answer to Damien’s post...
I’m sure my clutch is not as firm as you describe, so as will get me a new one to fit in the winter hibernation period. I better go OE as I have the black fan, which apparently doesn’t fit all non-OE fan clutches
My radiator is fairly new, less than 8k miles, and I have just replaced the condenser, so I know for sure there is (close to) zero debris in there. There was a bit between oil cooler and radiator, which I didn’t manage to get out while in there. That would have required bonnet to be removed, and I just decided that was not a step I wanted to make to remove 4 leaves...
Thanks !
#6
08-12-2018, 05:12 PM
Veteran Member
It also depends on how much the temperatures rise at low speeds. As I understand it, a little bit above "normal" is fine, so long as it doesn't keep going up and up. If it goes up and stabilizes, the cooling system is doing its job.
Someone should probably load a video of a known good clutch being tested with the flick test....
Someone should probably load a video of a known good clutch being tested with the flick test....
#7
08-12-2018, 11:37 PM
Veteran Member
It also depends on how much the temperatures rise at low speeds. As I understand it, a little bit above "normal" is fine, so long as it doesn't keep going up and up. If it goes up and stabilizes, the cooling system is doing its job.
Someone should probably load a video of a known good clutch being tested with the flick test....
Someone should probably load a video of a known good clutch being tested with the flick test....
I'll do this tomorrow and make a video if I remember. My clutchfan is new I put the whole thing in bolted together in a single go last year. Overall it should spin 1/4th at cold, and barely the width of a fan blade at hot. So maybe a quater turn max stone cold and 10% at hot, though I'd have to look through my pile of parts invoices to see whether this was the heavy-duty clutch or not. There is a HD version that fits the XJS that does grip alot more and thus forces more air through, its in Kirby's book.
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#8
08-13-2018, 01:00 AM
#9
08-13-2018, 02:11 AM
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#10
08-13-2018, 05:59 PM
Veteran Member
And from a different angle:
Both are on a cold engine, ambient about 20C. The blade moves about 1/4 turn.
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Some Day, Some Day (08-13-2018)
#11
08-13-2018, 11:07 PM
Testing it by spinning is almost useless.
Here’s how to test it properly :
http://fanclutch.com/PicsDocs/BorgWa...ives_Only).pdf
but to sum up, you should get 800-1300 rpm at 2500 rpm clutch speed, which is about 2000 rpm engine speed, that is if the clutch is not hot enough to fully engage (happens around 200-220F), but is not totally cold either.
Here’s how to test it properly :
http://fanclutch.com/PicsDocs/BorgWa...ives_Only).pdf
but to sum up, you should get 800-1300 rpm at 2500 rpm clutch speed, which is about 2000 rpm engine speed, that is if the clutch is not hot enough to fully engage (happens around 200-220F), but is not totally cold either.
Last edited by Mark SF; 08-13-2018 at 11:11 PM.
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xjsv12 (08-16-2018)
#12
08-13-2018, 11:15 PM
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#13
08-13-2018, 11:26 PM
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Testing it by spinning is almost useless.
Here’s how to test it properly :
http://fanclutch.com/PicsDocs/BorgWa...ives_Only).pdf
but to sum up, you should get 800-1300 rpm at 2500 rpm clutch speed, which is about 2000 rpm engine speed, that is if the clutch is not hot enough to fully engage (happens around 200-220F), but is not totally cold either.
Here’s how to test it properly :
http://fanclutch.com/PicsDocs/BorgWa...ives_Only).pdf
but to sum up, you should get 800-1300 rpm at 2500 rpm clutch speed, which is about 2000 rpm engine speed, that is if the clutch is not hot enough to fully engage (happens around 200-220F), but is not totally cold either.
Yeah, because all of us have temp probes and digital-photo tachometers sitting in out tool boxes, right?
And how the heck are you supposed to get the required cardboard cut-out in place on a Jag V12?
The spin method is satisfactory. If nothing else, if the fan free-wheels with no resistance, you know the clutch is bad. Lacking that, if unsure, you just replace it.....which is almost certainly easier than the 21-step test procedure described.
Cheers
DD
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xjsv12 (08-16-2018)
#14
08-13-2018, 11:29 PM
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#15
08-13-2018, 11:32 PM
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#16
08-13-2018, 11:46 PM
The situation where it is somewhere between totally dead and good as new is actually what leads to mild but chronic overheating, so common with the V12.
A digital tach is $10 on EBay.
You can can do without the temp probe and the cardboard, and most if the steps. Just start the engine, wait for the initial roar to subside, and measure rpm after a few minutes. The salient info is the 40% of shaft speed, increasing to 85% when locked up.
If you’d prefer to continue to guess, you are of course quite welcome.
A digital tach is $10 on EBay.
You can can do without the temp probe and the cardboard, and most if the steps. Just start the engine, wait for the initial roar to subside, and measure rpm after a few minutes. The salient info is the 40% of shaft speed, increasing to 85% when locked up.
If you’d prefer to continue to guess, you are of course quite welcome.
Last edited by Mark SF; 08-13-2018 at 11:52 PM.
#17
08-14-2018, 03:16 AM
Thanks for your replies.
I tried to flick this morning.I have it on video as well. Edit: I thought I had it on video as well...
It looked very much like what we see on VancouverXJ6's videos. Temperature was 17°C ambient and engine was cold.
Thanks Mark for your contribution. I like this more scientific approach to the testing, and I believe I have access to a tach at my job. One more task on the to-do list !
BR Leo
I tried to flick this morning.
It looked very much like what we see on VancouverXJ6's videos. Temperature was 17°C ambient and engine was cold.
Thanks Mark for your contribution. I like this more scientific approach to the testing, and I believe I have access to a tach at my job. One more task on the to-do list !
BR Leo
Last edited by leo_denmark; 08-14-2018 at 03:23 AM. Reason: ADDING INFO
#18
08-15-2018, 09:55 AM
Warm flick test: the fan rotates a lot easier when warm ! No need to wait for the digi-tech I have ordered on eBay...
2 hubs exist, and as my car is a bit of a Frankenstein I’m uncertain which one I have. The engine is from an 89 XJ12.
Can you identify from this picture, or should I take it off to be sure ?
#19
08-15-2018, 10:33 AM
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#20
08-15-2018, 11:04 AM
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Looks like the later Series III fan clutch to me. If it needs to come out anyway, then you have a good opportunity to measure.
Fan and clutch come out as a unit, I found it easiest to loosen the shroud and lift that up with the fan until the fan and clutch can be removed. Be very careful that the lower tips of the blades don't damage the radiator. You may not want to buy from them for shipping cost reasons, but Rockauto.com is good for listings and dimensions. The 89 XJS is the same part as the XJ12. An example: https://www.rockauto.com/en/moreinfo...178793&jsn=479
Fan and clutch come out as a unit, I found it easiest to loosen the shroud and lift that up with the fan until the fan and clutch can be removed. Be very careful that the lower tips of the blades don't damage the radiator. You may not want to buy from them for shipping cost reasons, but Rockauto.com is good for listings and dimensions. The 89 XJS is the same part as the XJ12. An example: https://www.rockauto.com/en/moreinfo...178793&jsn=479
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leo_denmark (08-15-2018)
