Wednesday, June 4, 2014

How to change the alternator in your 2005 Jaguar S-type R (Supercharged)

Changing the alternator on your S-type R is a bit harder than your your regular Jaguar. You have to remove the engine mount which includes supporting the engine, but is not as hard as it seems.

Here is the link for buying the alternator: Db AND0381 Alternator
Here is a tool that is relatively cheap and makes removing the drive belt much easier. Wilmar W84010 Serpentine Belt Tool

For the procedure:
  • First of all, disconnect the battery's negative terminal (for the love of God don't skip this step). Leave the trunk open so it doesn't lock up on you.
  •  You are going to need to get down there, so set up the car properly in jack stands in a hard level surface, somewhere not too hot. Is good to do this job when the car is cold. Here is a pic of the alternator which is by the right wheel from the bottom. 
  • The first thing to do is to disconnect the electrical connector that does to the back of the alternator. Then you want to remove the 13 mm nut that attached the alternator battery terminal, and remove that cable as well. When you remove the cable and the alternator wire, you want to move them out of the way, they are clipped to the block, undo the clip and push it out of the way (without braking them.)
  •  The next thing to do is to remove the belt. You don't want to take the belt completely out, you just want it out of the alternator drive. To remove the belt you need to put a 3/8 drive on the drive belt tensioner, push it counterclockwise and with the other hand undo the belt from the alternator. This tool makes the job much easier: Wilmar W84010 Serpentine Belt Tool

  • There is a bolt and a stud holding the alternator in place. The bottom bolt should be a no brainer, but you want to remove the rop nut first. I stick a short extension with a 13 mm 3/8 socket as in the pic below, stick your ratchet in there (an 90 tooth ratchet makes this a breeze) and remove the nut. Pain in the behind I know but you are saving money!

  • Then remove the bottom nut and long bolt, make sure you are putting all this bolts away in an orderly manner.
  • Now you have to remove the engine mount. To do this you have to support the engine, I do this by placing a jack with a piece of wood (the wood is so as not to stab or bend the oil pan) in the oil pan. Jack it ip slightly. Then you want to remove the top and bottom 15 mm nuts that hold the engine mount in place. Then jack up the engine just enough so as to be able to remove the mount. After removing the mount, you want to remove the four bolts that remove the bracket on top of the mount. This will give you plenty of space to remove the alternator.

  • With the mount out of the way you can remove the alternator.

  • A good habbit is to compare parts! In my case the alternator back was offset but it wasn't a problem.

  • To install just reverse the steps in the above procedure, but drink a beer at some point!


  1. Is this procedure any different on the non-supercharged 4.0L engine?

  2. Note, the electrical connector is held on by a little latch which is hard to see. The latch is on the face of the connector closest to the outside of the alternator. This is true for the older 4.0L jaguar as well even though the connector is a little different in shape.

  3. I just got the alternator out of my 01 4.0L jag and it was a pain in the butt. However, with my new found knowledge, you will have a much easier time of it.

    The top bolt will not come off easily. Apply penetrating oil as needed. Loosen the bolt by hand. It's a 10mm bolt on the 4L. Trying to use a hand ratchet to unscrew the bolt is a exercise in frustration. There is not enough room to maneuver. A 90 tooth ratchet is useful as Daxter said. However, you can also use an impact wrench. Make a socket extension about 15" long. This will allow you to put a full size impact wrench up into the engine bay.

    You don't need to unmount the engine either. You can just wiggle the alternator out if you use the body of the alternator to push a coolant line out of the way.

  4. Also, there are two flanges of metal on the lower part of the engine which appear to be die casting handles or something. One of them will block the removal of the alternator. Just cut part of it off at an angle. It seems to serve no structural purpose. Cutting off that corner will greatly ease removal and re-installation.

    I also ended up using a non-oem rebuild alternator because the cost of rebuilding my alternator was too high. It did not trigger the battery warning light like some people on the forums said it would.

    The bad alternator had already been rebuilt once before. It seems like the engine layout design is bad because it places the alternator in a low position where it can be splashed by water. There is a plastic piece to protect the alternator but it does not fully protect it. Just screw some extra pieces of plastic on the plastic part that is already there. Otherwise, every time you go into a car wash with an underbody washer you will be spraying water onto your alternator.

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