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My re-commissioning of my friends 1996 6 Litre Convertible continues with the wiper motor taken out and dismantled to try and resolve a very slow and noisy operation. I had some partial success but only after managing to jam my finger between 2 of the crank-and-link arms whilst they were operating. The most incredible pain ensued as the linkage seized, and I will lose the fingernail but at least my finger survived. Lesson learnt! With no indicators working I established that the flasher module had failed (never had that before!) so I swapped the module off my own 4 litre temporarily. The upshot was that after months working on the car, I've now managed to get an MoT pass on the car! Hurrah! Even the emissions were spot-on, so I've just got that second fuel pump relay to purchase and fit, an oil and filter change and I've finished with the engine.
However, the alternator doesn't seem to be working at all, with tests at the bulkhead and battery only indicating basic battery voltage after start-up, although the instrument light is not illuminated when running. After 30 mins of idling, the battery then flattens and the car cuts out. Having read another recent thread, I was almost hoping that the car had a load dump module that I could disconnect, but the wiring diagram for a 95/96 car doesn't show one.
So, before I go to the effort and expense of removing the alternator and getting it rebuilt / replaced, has anyone got any suggestions for any other tests that I can do directly at the alternator to try and pinpoint the problem? (not even sure how I can get to the terminals whilst in situ?)
I've decided I'll remove the alternator and take it to the guy who rebuilt what I think is a similar 120amp unit on my AJ16 4 litre.
However, I'm not sure of the easiest way to do it. I understand from the 1993 Workshop manual that the earlier 5.3 alternator should be removed from above. I don't have the workshop manual for the 94-onwards 6 litre. But I found a post from an owner of a 94 6 litre that said the removal was a fairly simple process done from below.
Does anyone have access to the section of the 94 or later workshop manual that details how to remove the 6 litre alternator? Or does someone have practical experience of the best way to do it?
Paul
I do not think the alt can be removed from below on any V12 XJS. Could be wrong, but...
If it helps, on a pre facelift 5.3 HE the procedure is not that difficult, but it is a bit complicated:
Battery disconnected and A bank air box and filter off
Loosen but do not remove the long bolt on top of the alt (fixing it to the bracket on the block which supports it) on which it pivots
Loosen off the adjusters for the other belts, which also involves loosening off the blocks the adjusters act against.
The water pump/P-S belt is the most annoying, you have to loosen the P-S pump lower bolt, the adjuster and the block AND the bolt holding the adjuster eye to the block. Then you can JUST move the pump enough to get the belt off.
Remove the other belts.
Jack up the front of the car to loosen off the alternator adjuster and the adjuster block fixing and note carefully the position of the adjuster block fixing and how it is fitted!
Remove belt.
Undo electrical connections
From above now remove the long bolt on which the alt pivots and withdraw it.
Lift up and out.
Fit new belts on reassembly! All this is doable without removing the fan and shroud; but space is tight and nucckles are vulnerable! You will, having done it, realise one of the great maintenance advantages of an all-electric fan setup!
Last edited by Greg in France; Nov 13, 2025 at 12:31 AM.
Tks so much Greg. That sounds more like what I expected! I don't know if the 6 Litre had a fundamentally different setup to the 5.3 (other than just a more powerful alternator) hence my nervousness. Briefly reading your instructions (and not being with the car at the moment), it seems that a number of the tasks need to be done from under the car, even though the alternator then comes out from the top. Is that correct? Also, do you just take off the case of the air filter or do you need to fully remove the filter case plate from the inlet manifold as well?
Part of the reason for my confusion is that I found this post from many years ago on Jag-lovers from Steve who was a knowledgeable owner which implied that removal from below was really very simple?:
On the '95 XJS, the alternator is a simple job. From underneath – belt off (one bolt to release tension), two bolts (holding the alternator to the bracket), two wires. Assembly is ‘‘in reverse’’.
I then read this post from the owner of a 1995 XJ12 saloon (which I appreciate may have a quite different configuration and access):
An update and tip for others attempting this repair. To remove the alternator, from under car, remove the 4 stabilizer bracket bolts and then remove the bolt on the right stabilizer bushing, disconnect the eccentric rod and loosen the bracket so it will swing down. Then disconnect the triangular shaped bracket holding the power steering line, disconnect one of the clamps that holds the rubber hydraulic line under the radiator. The upper bracket bolt is 17mm front and back. The main power line wire nut is 12mm and the small wire is 5/16 SAE.
Both of those posts seems to imply that I don't need to worry about all of the other belts etc which would naturally be much easier, hence my desire to fully understand this before I jump in and start pulling bits apart. And I'm not in front of the car right now to appreciate the location and setup of these various bolts, brackets etc that are being described. So, I might have to try and get the car up on a ramp and have a really good examination. Aaargh, the joys of being an XJS Custodian!!
Any 6 litre owners, please feel free to jump in and put me out of my misery!
Paul
If you do not renew the belt, then you can get away with just getting it off the alt pulley, yes. And then you do not have to remove the other belts. Good point.
It is only the adjuster and the block it acts against that have to be accessed from under the car, even if all the belts are changed, the other fasteners are acessed from above.
Never having worked on a 6 litre, I cannot comment for sure on removing the alt from below; but I doubt it!
Just the unclickable outer of the airbox needs to be removed, as the trumpets and ducting (if there) is in the way of top access to the alt.
Do you see any voltage increase at all on increase of RPM - the Jaguar setups are infuriating and charging only gets going above 1000 rpm, mine would start charging and stay charging but not until I passed sufficient RPM to trigger the process, the batteries on these cars are also too small in my opinion.
I thought the 6.0's were a poly V serpentine belt ??
No change when revved and earth points seem sound, although haven't checked wiring points on alternator itself. 6 litres on XJS and X300 all use the same original multi-belt setup.
Paul
If you do not renew the belt, then you can get away with just getting it off the alt pulley, yes. And then you do not have to remove the other belts. Good point.
It is only the adjuster and the block it acts against that have to be accessed from under the car, even if all the belts are changed, the other fasteners are acessed from above.,
Never having worked on a 6 litre, I cannot comment for sure on removing the alt from below; but I doubt it!
Just the unclickable outer of the airbox needs to be removed, as the trumpets and ducting (if there) is in the way of top access to the alt.
Tks Greg.
If I don't have to remove all the belts, that seems a lot easier. But from a quick perusal of the parts diagram, wouldn't I still have to remove that idler / tensioner & belt in place of the US airpump thing on UK cars, in order to extract it through the gap above?
I have a 94 6.0 and I'm the process of sealing up oil leaks, so a lot is out of the engine bay at the moment. I took some photos and measurements and I think the alternator needs to come out the top, or the anti-roll bar removed. I measured the alternator and it's a bit under 6" diameter and the clearance between the rollbar and subframe is a touch under 5". If the bar wasn't there, it would come out the bottom easily. That being said, I don't have the fan, radiator or condenser in my car, so I have lots of space to maneuver! I'm not sure of the space in front of the rollbar to radiator to know if the alternator could drop out there. Mine is LHD, so I don't have steering to work around either.
I have removed the alternator on a 1992 Series III V12 and it came out the top without too much of fight. The air pump needs to be removed and then there is enough space to bring the alt up the top.
I think if the car was fully assembled, out the top might be the path of least resistance.
Craig
Last edited by Jagboi64; Nov 13, 2025 at 11:31 PM.
That's really helpful, tks for chipping in! Even with all your equipment stripped, it now seems difficult to see how it would come out from the bottom. And of course, you don't have the rad etc in situ, so I agree, I'm not sure it can come out in front of the ARB either. It's a shame as it seems removal from below should be the easier route. But at least I understand what I'm looking at now.
I wonder how these other guys actually removed it from below?
I think I'm going to have to get the car up on a ramp first.
I've just thought - As well as the alternator not seeming to be charging the battery, the charge light doesn't come on when the ignition is powered on. I remembered Doug mentioning in a previous thread about the alternator in an earlier 5.3 HE, that a blown bulb could stop the alternator from being excited and start charging.
So I wondered if this might be part of the problem. But when I looked at the 96 6.0 wiring diagram tonight, it seems to potentially be quite different on the late models. It seems as if an output current from the regulator is what powers the instrument light, and then presumably extinguishes it? Is that others would infer from the diagram below? So, the reason that the light is not illuminated with the ignition on is because of a failed alternator / regulator, as I suspect?
Usually the bulb is needed to give some current draw to the coils ( I forget if it's the stator or field coils) to create a magnetic field to start charging. A blown bulb absolute can cause an alternator to not charge. I'd start there, it's probably a lot easier to change a bulb than to remove the alternator!
How many miles on the car? It's a possibility that the brushes are worn out, but often you get intermittent charging for a while before it goes completely dead.
I think I'll pull the instrument cluster and check the bulb first.
Also, I took a quick photo of the setup on the car, and it does seem as if it will be difficult to manoeuvre the alternator out the top with that idler and belt (that replaces the airpump on UK cars) still in place? Does that sound correct?
You can probably leave the idler in place, and wiggle the alternator rearward. I've only worked on cars with airpumps and had to remove them, so I'm not sure. The idler wouldn't be that difficult to remove I suspect
Well, i dropped the instrument cluster and removed the bulb and tested it as well as swapping it with an adjacent bulb. And i can't get any bulb illuminated, so it does seem as if the regulator has gone in the alternator. Looks like I need to remove it.
Compliments of the season to you all!
,
With too much food consumed, I decided that I really had to get the alternator out of my friends 6 litre today. Jaguar World Monthly came to do the photoshoot and write the article for the magazine recently, and I really would like to get the alternator sorted if I can before the car goes to auction.
So, after the various inputs and debate, I can now categorically confirm that the alternator on a late 6 litre car DOES come out the bottom, rather than the top, on a RHD car! I'm not sure, but it just might be easier on a LHD car as the PAS pipes may not be in the way?
Maybe the Nippon Denso that is fitted on the late 6 litre is slimmer than the earlier 5.3 alternator? Is that why the 5.3 alternator has to come out from the top?
I admit it wasn't easy, it took me 3 hours to finally get it out. Some of the difficulties were occasioned by the lack of use of the car over recent years. I'll post some photos when I do the reassembly, but in summary, this is the way I did it, and the associated challenges. It wasn't quite as simple as the steps below as I was trying things out to find the best way. But in retrospect, this is the way I would suggest.
I didn't have access to a ramp, so I started by jacking up and supporting the front right hand side of the car so I could lie underneath
1. Remove the closing panel / undertray attached to the plastic bumper. Of course all the screws will be partially seized so be very careful not to round them off. And then when you remove the panel, an awful lot of debris dirt, leaves etc will fall onto your head, into your eyes, and onto the floor!
2. Remove the cross-brace under the engine, that is fitted on late convertibles (maybe Coupes as well?). Of course this then means lowering the car, removing the jack / axle stand, and once the brace is removed, refitting the bolt on the jacking point and re-raising the car.
3. From the top, remove the right hand air filter outer case and the filter. Also disconnect and remove the air intake pipe that goes from the filter to the panel above the radiator.
4. From underneath, remove the bolt that attaches the tension adjustment stay to the alternator. I decided it was easier to do this first, rather than disconnect the adjusting nuts as the threaded adjustment rod was rusty anyway. And the whole stay needs to be removed anyway. Even basic access to the bolt (which was very tight!) is very difficult as you have to clear the anti-roll bar with the ratchet / breaker bar and socket. I had to try a whole combination of breaker bar lengths, extension sockets, wobble sockets etc until I finally managed it.
5. Now remove the nut and two long bolts that hold the triangular plate that mounts the other end of the tension adjustment stay to the engine. Remove the plate and the adjustment stay. Similar access problems and you have all the belts in the way as well. The upper pivot bolt of the alternator is still in place at this point so the alternator hasn't moved and the alternator belt will still be tight.
6. From the top, remove the large electrical connector on the back of the alternator. Similar access problems. I had to use a cranked ring spanner in the end as I couldn't get any socket access in there.
7. If I had known how to do it, I would also remove the multi-pin electrical plug from the back of the alternator at this point. Unfortunately, I couldn't work out how to do it, so decided to leave it until the alternator was ready to come out. It actually just requires a push of the black plastic tab, which I'll show in the reassembly photos.
8. Now from the top, undo the nut at the back end of the top pivot bolt. This is a real pain to get to with a a socket as you're very close to the engine block and its really hard to get socket and ratchet access in there. Another session of trying different ratchet heads, socket lengths etc. And of course, it was really tight! And I couldn't get a socket on the front bolthead from the top as all the pulleys and belts are in the way. Eventually, I managed to crack the rear nut loose a fraction and eventually worked it off.
9. With the top pivot bolt nut off, and working alternately from the top and the bottom, I eventually managed to lever the alternator a fraction to get the tension off the belt and slip the belt off the pulley from below.
10. From the bottom, you now need to loosen the top pivot belt. Yet again, another really difficult task as all the belts and idlers are in the way. I eventually found a combination of a socket and ratchet that got it started to come out. I then had to use an open-ended spanner to continue as the belts and idler pulleys preclude the continued use of a socket. I finally managed to extract the bolt from the top.
11. From the bottom, I then started to work the alternator forward and back in its pivot until it finally dropped down. At this point, I still didn't know if it was going to come out from the bottom, between the front edge of the subframe and the anti-roll bar.
12. With the alternator now free, I turned it through 90 degrees with the pully facing down. I then returned to the top and worked out how to remove the electrical plug from the back of the alternator (which was now facing up).
13. From below, with everything free, I then started to work out how to wiggle the alternator through the gap. I had to turn it around a few times and try different positions. But after a lot of persuasion, you can just find a position where it will scrape through the gap!
So there it is! I now need to take it to an auto-electrician to get it assessed and repaired. And then I need to work out the orientation to get it back in that gap and get all the bolts and brackets back in place. Let's hope it's easier re-installing it!
Testing 1996 6 Litre Alternator
