Took the car out today, started on the button fine, no issues the ecm is clear of any codes ( i check it often ) went for a long drive ( around 60 miles ) opened her up onthe motorway, got to destination all ok.

after about an hour got back in the car two thirds of the way home " battery not charging" came up and the cooling fan was on full pelt until i got home.

Came in and had a good read of the forum so I did some checks.

Using a calibrated Fluke meter i got the following.

1. Rear fusebox fuse 5 on contiuity check was good fuse not blown
2. Chassis ground to battery positive gave me 12v
3. Negative terminal and positive terminal directly on the battery 12v
4. Start car check while engine running.
5. Chassis ground to Battery positive terminal gave 11.5v
6. battery negative to battery positive gave 11.5v

I have checked the service paperwork and the battery was replaced 16th december 2022 with a Bosch battery with 4 year warranty, so the battery isnt that old.
Will order a new alternator tomorrow, there is nothing in the paperwork showing a replacement at anytime, will do the belt at the same time.

I will try and get under the car to check the alternator cables just in case however, I am pretty sure I need to replace it.

 

I'd personally check the tension on the belt next, but everything else you did seems to lead to the alternator.

 

I am just going to replace the belt and the tensioner at the same time, check the other pulleys also.

 

Had this message two weeks ago - alternator replaced and all good.
Volts at battery terminals should be ≈14 with engine running.
Good you checked fuse - that's "command" volts from ECU to alternator.
While you're there, check the "vacuum pump" located close proximity to alternator; mine was leaking oil onto alternator.
Vacuum pump lasts forever, but seals wear out. Cheap seal sets available on Ebay. Easy fix.
Good plan on replacing serp belt and tensioner idler.

 

Sean W is saying, If the belt was slipping, you don't need an other alternator... Measure the battery with the car running....

 

Interesting. I have the same problem. I replaced my alternator and negative cable which includes the BMS to no avail. I have a new Interstate AGM Battery. Read my thread:

​​​​​​https://www.jaguarforums.com/forum/x...e-rate-239220/

 

i did measure with the car running , its in the first post.

1. Start car check while engine running.
2. Chassis ground to Battery positive terminal gave 11.5v
3. battery negative to battery positive gave 11.5

I checked the car when running, put my fluke meter to the chassis and to positive, gave 11.5v then did the negative and positive terminals, the same 11.5v. So i will do the belt first, if it will stop bloody raining!!!! this week. Will order the belt tomorrow and fit tuesday see what happens, if it is still there then i will have to look at the alternator, I dont think that a battery fitted 8 months ago is the issue.

 

The idle tensioner should be more of the cause, than an older belt.

 

Tracee had a vacuum pump leak oil onto the alternator. Oil on the strap and it would slip...
And the tensioner should be checked.

 

Shone a torch into the space where i could see, the alternator is like new, all shiny in there, the belt looks good also. its 11pm here and I cant get my giant hands in there to check it, i will jack it up tomorrow and check it all. I will put a mark on the alternator ulley wheel and see if its turning or not. check the cables etc.

I am hoping i can get a replacement denso alternator either tomorrow late afternoon or the next day from my local motor factors also a belt etc.

 

I replaced my alternator with a Denso. It is not a difficult job. You don't have to remove the idler pulley if you use a ratchet open wrench on the upper bolt. When you remove the 2 bottom bolts, and disconnect the battery cable loosen the top bolt with the closed ratchet wrench and drop the alternator to unplug the wire connector. The wire connector has thin wires and you don't want to break them at the connector. The connector is a little difficult to disconnect without dropping it to gain access.

 

did you have to undo the engine mount lower nut, lift the engine and remove the mount?

 

No. There are some YouTube videos of replacing the alternator on the 5L engine for different models.

 

So I spent this morning taking the under tray off getting everything ready only to realise all the advice is for left hand cars. This is a uk right hand drive. So right behind the engine mount is the steering column. So I can't remove it that way or downwards. I don't have the tools to drop things etc. So I have to get it to a garage to be done.

 

Interesting!

 

So I have read the manual again and followed the procedure as far as I can, my biggest issue is I have really large hands, I can't get in to loosen the tensioner to take the belt off, I can't get my hand in the subframe to disconnect things either, I have tried everything to get this done. I don't have a long enough socket to undo the engine mount lower nut. And the list goes on. For the first time a car has beaten me and it's going to a garage to be done.

 

Having removed the belt a couple of times I can confirm that you don't need to get your hands down there to loosen the tension on the belt. Space is indeed limited by the secondary air injection pipework, assuming that yours is the same as our 2006 4.2, but all you need is to lower a socket extension with a 3/8 square drive into the square hole at the top of the tensioner, at the opposite side to the pulley itself.

Richard

 

Hi richard. i managed to see the 3/8 square hole you were on about, so the belt is ok to loosen.
Looked everywhere for my long reach sockets, bloody things have dissapeared. I alsonoticed that putting a new belt on was going to be interesting also, not much room to thread it around.

I needed ths done today as I have to take kids to dentist tomorrow ( had to cancel it now ) and i need it to get to work on thursday (looks like thats out the window now also, boss will be very pissed off )

I might give it another try tomorrow if i can get some long reach sockets localy and a few other things. failing that its off to the local jag independent specialist.

 

The belt is tricky to remove and fit because of the secondary air pipework (the 5.0 engine does not have this issue) but after a few goes at it I worked out the best way to do it. I posted the best method six months ago so I'll look it up now and copy it here.

"The oil filter is best removed first and the bonnet secured in the vertical position with the struts disconnected. You don't need to drain down the oil system as you will only lose a small amount of oil (a couple of hundred mls) before it stops dripping. If you store it carefully, you can use the same filter once you have fitted the new belt. Your two access points are now an upper access on the left hand side of the engine from above, where the intake ducting was removed, and the lower access point where the oil filter was removed.

Standing on the left hand side of the engine, make a sharp loop in the belt and feed the folded loop of belt diagonally downwards towards the lower right corner of the engine where the alternator pully sits. Thread this loop of belt in the gap between the top of the crankshaft pulley and the bottom of the waterpump pulley, ensuring that you feed it in the space between the front of the block and the back of the secondary air injection pipes.

Once you have pushed the loop far enough for it to be close to the alternator pulley, then go through the oil filter access point from below and pull the loop so that it goes over and either side of the alternator pulley. The lower run of belt should now be resting on top of the idler pulley which is its correct location.

Now return to the upper access point and take the upper run of belt and feed it over the top of the waterpump pulley. Then return to the lower access point and pull the loop from below the alternator pully and keep pulling it downwards until it is hanging below the engine. The ribbed side of the belt will the turning on top of the waterpump pulley and the smooth side running against the idler wheel. By pulling the loop downwards you are pulling the long length of belt which is still hanging over the wing of the car into the space in front of the engine. This helps to avoid the belt getting caught up in its own length as mentioned above.

Once you have a reasonable length of belt left to work with from above, you can feed the top run, which is already over the waterpump pulley, down the outside of the power steering pump pulley, taking it between the engine block and the secondary air pipework as before, and the a/c pulley and then, from beneath, round the crankshaft pulley. As you pull more belt down from below, the loop which is hanging down below the alternator pulley will simply move upwards and should not get in the way of what you are doing through the oil filter access.

Finally, from above, you should be able to pull the run of belt which is lying over the top of the idler pulley towards the tensioner, once again keeping it behind the air pipework. You will need to twist the belt 90 degrees as you push it behind the tensioner pulley but you will not be able to feed the belt over the tensioner until you have introduced some slack. I did this by slipping the belt forwards off the a/c pulley from below. You can then complete the routing round the back of the tensioner pulley.

I then used a socket extension with a 3/8 inch square drive to move the tensioner across by standing on the right hand side of the car and pulling the socket extension towards me whilst my Son lay under the car and slipped the, now loose, loop of belt back over the a/c pulley. Access for this is easy through the oil filter gap.

It sounds simple enough but is actually very fiddly so take your time and use a torch to check the the belt is properly located on the waterpump pulley and the crankshaft pulley. These both have a high lip and the belt needs to be positively pushed over the lip but they can be tricky to see clearly. Visibility on the PAS and a/c pumps is better and you can also see these through the lower left-side wheel arch."

I just used a breaker bar with a 3/8 inch square drive to move the tensioner. You can just use the bar. No socket is required as it's the drive that engages with the tensioner.

I hope this helps.

Richard

 

I came back out and have got to the point of the engine mount being free, I cannot get it it as the steering link is in the way, there is still no way to get the mount out let alone the alternator. Everytime I raise the engine up its making noises I don't like. So I am going to put it back. Now I have to get it trailered to the garage, an extra cost. The workshop manual leaves a lot to be desired. Very very poor compared to the WIS manual I had for my merc. Nope I'm done.