1995 Jaguar XJS Window Motor Replacement Options?

Hello, I have a beautiful 1995 Jaguar XJS convertible and need advice regarding window motor / regulator replacement. My understanding is that these parts aren’t available anymore, so the only option is to source used parts. However, I recently did so at a cost of $800+ NOT including parts (which totaled $500 altogether) only to discover that the the left hand drivers side (USA) is still underperforming. I can already tell I’ll need to replace it again soon.

My question is: is there a motor / regulator set intended for a different Jaguar but still compatible with mine and - ideally - still in production? Or somewhere I could source a used set with higher confidence in the condition?

Really frustrated and not sure how to proceed, but I have to do something because while the window at first appears to close all the way, it doesn’t really, which is a huge problem if I get caught in the rain.

To be clear, a local mechanic with experience working on Jaguars performed the services. I am not a mechanic. Also, I already replaced the window and convertible top switches with new OEM switches, so that is not the problem.

My 82 XJS coupe had a window that laboured and stalled. I sprayed the runners with silicone lubricant and it worked fine and two years later it’s all still good. Maybe a different problem but just saying….



I’m sorry to hear this. We can help.

You don’t sound like you know whether its the tracks or the motor. Let’s assume the motor is good? I would hope the mechanic would have been able to grease that up, or at least diagnose it for you if it were the culprit?

On the facelift models, there are three tracks to be concerned about. If you’re looking at the door, there’s a track that runs along the left and right hand side of the doors, basically in line with the edges of the glass. Those should be greased up. Some people like white lithium, I prefer a silicone paste. I’ll post a link at the bottom of this response.

More importantly, there is a track at the bottom of the door. This track is more important because there is a plastic part that does the lion’s share pushing the window up and down those two tracks I previously mentioned.

If you take the time to remove the door card from the door, you can easily (well maybe not entirely easily) get to these tracks, especially the bottom. Let me know if you think you can, and are willing to do that. I can send you some pics on how to remove the card. It won’t take that long, and it won’t require special tools.

I like to use 3M Silicone Paste 08946

The best way to apply it is on your fingers (use a rubber glove if you prefer) and really work in there with your fingers. Sprays and liquids might be too viscous for the long term.

You might also need to clean out any varnished, or sticky residue that was there before. I have never found the need, and just apply this paste on the tracks and smother it as best I can.

Presumably you’re talking about the door windows on your convertible. On a '95, that would be a Bosch with an 8-tooth pinion:

Window Motor Bosch aftermarket RTC3821P 115736-Large

Unfortunately, stupid expensive when you can find them. So expensive, in fact, that there are companies offering cheaper aftermarket versions; this photo is actually one of them.

If you wish to try your luck at junkyards, know that the same motor with the same pinion was used in some Range Rovers as well as the 1990-96 VW Golf. There are several other models of cars, including Mercedes and Volvo, that use the same motor but with a different pinion – meaning you might be able to swap the pinion, or possibly the motor itself.

You can actually buy a replacement brush assembly for the Bosch motor, although it’s hard to imagine the one you have is worn out.

On cars with the earlier Delco motors, it has proven worthwhile to install relays to power the windows. This gets more voltage to the motors themselves, eliminating the voltage losses in long wiring runs and the switches themselves. However, it’s possible – even probable – that the 1995 already has relays.

If you happen to be talking about the rear window motors, on a 1995 they should be the same Bosch motors except with a 14-tooth pinion. Those can be found in a Mercedes W123.

BTW, if you’re up for it, it is supposedly fairly straightforward to replace the Bosch window motors and regulators in entirety with the Delco system from the up-to-1987 XJ-S. You don’t want the 1988-89 Delco, trust me. But the up-to-1987 uses an unusual motor that can be easily replaced with the motor from a 1977 Camaro, dirt cheap, available anywhere, and totally bulletproof. The hard part of the job is finding the regulators from an up-to-1987 XJ-S.

He’s already replaced the motor once. I have to believe that the tracks need attention. Most people simply address the side rails. The bottom rail is the one that I think needs the most attention.

I could be wrong about the motor, but what is the chance? Unless a rail (or more) are bent?

The motors are robust and don’t seem like a common point of failure. There have not been many complaints of the door motors on these forums. The rear quarterglass motors have been known to have trouble, but not the window motors.

Thanks for all of your input. If I end up needing to go this route, can you recommend a specific aftermarket model for me to look into?

Thanks, this is really great insight. I’ll definitely share your hypotheses with my mechanic next time I bring it to the shop. He may have told me, but I don’t recall whether or not we discussed what condition the tracks are in. Hopefully it’s as easy as greasing them up.

What I do recall of his explanation is that the driver’s side window would be used the most, so it makes sense that it would be worn more.

Here’s another clue: there’s a slight (nothing alarming) thud when I close the driver’s side window all the way. Before replacing the window motor / regulators, this happened with both the driver’s side and passenger side windows. The passenger side no longer does this and appears to operate as intended.

Actually, Jaguar used the “square case Delco” motors in the doors in 1988-89 and in the rear quarter windows in the convertibles up until 1992. That means they used them in the convertibles for a couple of years after they decided they were a hopeless POS and quit using them in the doors. Reportedly when an owner complained about the motors in the doors, Jaguar just upgraded them to the later Bosch motors.


I wouldn’t worry about the thunk. Mine is the opposite. Passenger still does it, drivers does not. There’s something on the window stop that probably came off. I spent some time trying to figure it out, but I gave up. That was years ago, and the windows continue to operate just fine!

Drivers side window being used more doesn’t really explain the situation to me. It’s a small two seater convertible. It’s not like the passengers side window isn’t being used at all. If anything the fact that the drivers window is used more, could indicate the window rails should be in BETTER condition?

Regardless, you shouldn’t be going through window motors. Something is off. My bet is the rails, since you already replaced the motor AND regulator once.

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Just for my 2 bits worth … I did what Kirby said… put earlier version of opener on my 88… Could not believe the difference in performance

Interesting… now you’re gonna make me fix something that isn’t broken…not cool.

Is there some kind of part number I can use to look these things up?


Yeah, but your '88 came with the square-case Delco. Unmitigated crap. Even Jaguar resorted to replacing those with the later Bosch. This car came with the later Bosch, shouldn’t be having as much trouble.

Still, I agree, if you want a bulletproof window system, the early round-case Delco is the way to go. Those things are hard to hurt. Of course, you’d be adding about 20 pounds to the weight of the car.

Lemme see if I can show some photos of what we’re talking about. Here’s the early round-case Delco:

Window Motor Delco round case s-l640

Now, if you go looking for this motor, you’d better be looking at Jaguars in a junkyard. It’s supposedly made by “Delco of England”, never seen in the US, pretty much impossible to find or service.

But then somebody found the motor from the 1977 Camaro:

Not a round case! Try to avoid calling it a “square case Delco” as we use that term to describe a later motor that’s a cheap POS. This is a solid machine. And while it looks different than the round case Delco, note that the mounting screw locations, the drive gear, and even the spring clutch assembly appear identical (one of these is a RH motor and the other is a LH, remember that both come in RH and LH versions). So while it may look different, the Camaro motor will bolt right in and work great. And it’s priced – brand spankin’ new at any AutoZone or Napa – like Camaro parts.

Can’t go that route without the early XJ-S regulator, though.