Donate NOW and support Jag-lovers!

IMPORTANT! We have moved! The new site is at www.jag-lovers.com and the new Forums can be found at forums.jag-lovers.com

Please update your links. This old site will be left up for reference, until we can move all the old content over to the new site.

Volunteers wanted! Please help us move information from these pages to the new site, and also join us in providing new, exciting content.



Serving Enthusiasts since 1993
The Jag-lovers Web

Currently with 3,166 members





Jaguar V12 Fan Clutch

Jaguar V12

Thermostatic Fan Clutch -

One-Bolt Type

The following are some pictures of a 1-bolt style fan clutch sent to Kirby Palm by Ed Sowell.  This particular one appeared to be in good condition, but Sowell reported that replacing it cured a problem he had with overheating in stop-and-go traffic so there must be something wrong with it.

Front:

Rear:

If you happen to have a copy of Haynes manual 478, this type fan clutch is illustrated in photos 49.12A, 49.12B, 49.13, and Fig. 2.7.

Info:  The center bore is 15/16" in diameter and 15/16" deep.  The diameter that the fan fits around is 3-3/8", and the fan mounting bolt holes are on a 3-15/16" diameter circle.  The OD of the housing is just a hair under 6".

Note that the type fan clutch shown is used on mid-70's XJ-S's and XJ12's.  The later XJ-S and XJ12 came with a different type of fan clutch that mounted with four bolts to a flange on the pulley shaft.  And reportedly the very early XJ12's, prior to the introduction of the XJ-S, had a different type clutch that mounted with four bolts.  See FanClutch.html for pictures of the late-70's-on 4-bolt style fan clutch.  The early XJ12 4-bolt fan clutch is illustrated in the Haynes manual in Fig. 2.6, but as yet there are no teardown photos on this site.  Note that Haynes describes Fig. 2.6 as applying to the XJ-S, but that appears to be an error; the XJ-S was apparently never fitted with a 4-bolt fan clutch and a metal fan.

Without further ado, on to tearing this unit apart and taking pictures of the innards.  There's no point in trying to rebuild it, as replacement is not all that expensive (especially if you choose a non-Jaguar substitute); the only reason to rip it open is to see how it works!

On the front there is a crimped edge in the circle between the fins at the center and the fins around the outer edge.  This crimping was cut off and the unit popped right open.  Here's the housing:

The red circle is a square cross section O-ring for sealing the cover to the housing.  It is very soft rubber, and was in good condition.

Here's the cover:

Here's the rotor that was in the middle:

And I even took a picture of the back side of that rotor:

The only difference between the two sides is that little circular rib around the hub area, but that doesn't appear to be functional; it's just a machining mark.

Compared to the unbelievable complexity of the 4-bolt fan clutch, this thing is laughably simple!  No grooves, no vanes, no compartments, no thermostatic bimetal elements, just a disk rotating within the housing.  There's not even a bearing!  If there is any thermostatic control at all, it's in the characteristics of the viscous fluid itself.

There appeared to be water mixed with the viscous fluid in this fan clutch.  That would indicate a seal failure; in fact, the seal on the back side appears to be NFG.  Since the fan clutch was probably initially totally full of viscous fluid, it's probable that some leaked out prior to this water leaking in.  Whatever, water in the works would explain the problems that Sowell was experiencing.  It may be wise to try to keep the outside of this type fan clutch clean, and when dark goo appears on it, replace the fan clutch.  Other than the appearance of dark fluid eminating from the seals, it would be difficult to ascertain whether this type fan clutch is in good condition or not.

It may be possible to replace the seals in this unit; both of them press in from the outside.  There is a bit of peening around the edges to secure them in place, but not enough to prevent servicing them.  It should be possible to pry the old ones out and press in new ones; the only problem would be making up for any lost viscous fluid while they are out.

It would also be possible to rebuild this unit.  After cutting the crimped edge off to separate the cover from the housing, there is simply no need to provide any sort of retention to put it back together; the four bolts that hold the fan to the clutch will also hold the cover on the clutch.  Again, the big concern would be in trying to find a suitable substance to fill the clutch with when reassembling.

Of course, by the time you have purchased two seals and a tube of goo, you're probably going to have spent nearly as much money as a new clutch would cost.
 

Return to pix page

 

Please help support the move to the new site, and DONATE what you can.
A big Thank You to those who have donated already!

 


       
       
       
       

Go to our Homepage
Improve your Jag-lovers experience with the Mozilla FireFox Browser!

  View the latest posts from our Forums via an RSS Feed!

©Jag-loversTM Ltd / JagWEBTM 1993 - 2024
All rights reserved. Jag-lovers is supported by JagWEBTM
For Terms of Use and General Rules see our Disclaimer
Use of the Jag-lovers logo or trademark name on sites other than Jag-lovers itself in a manner implying endorsement of commercial activities whatsoever is prohibited. Sections of this Web Site may publish members and visitors comments, opinion and photographs/images - Jag-lovers Ltd does not assume or have any responsibility or any liability for members comments or opinions, nor does it claim ownership or copyright of any material that belongs to the original poster including images. The word 'Jaguar' and the leaping cat device, whether used separately or in combination, are registered trademarks and are the property of Jaguar Cars, England. Some images may also be © Jaguar Cars. Mirroring or downloading of this site or the publication of material or any extracts therefrom in original or altered form from these pages onto other sites (including reproduction by any other Jaguar enthusiast sites) without express permission violates Jag-lovers Ltd copyright and is prohibited
Go to our Homepage
Your Browser is: claudebot, IP Address logged as 44.204.218.79 on 28th Mar 2024 17:29:02