A few years ago I replaced the accessory belt and pressed new bearings into the idler and tensioner pulleys on my XK8 as the belt was cracking slightly and the pulleys were sounding a little noisy. The entire job took around an hour as access to everything was so easy. Last weekend I decided to do the same job on my Son's recently acquired 2006 XK 4.2 as the belt was occasionally making a very slight chirping noise and the engine is basically the same so the job would presumably be similar. How wrong I was!

I did some research and found that a JTIS had been issued involving a change of idler pulley on the early XK's from a flat pulley to one with raised edges. I could see that My Son's engine still had the original flat pulley so I bought one of the new design to simply swap the two over.

The problems soon became evident because access to the belt and pulleys on the XK is terrible compared to the XK8, primarily because of the secondary air system pipework and the fact the the tensioner pulley faces toward the engine so the belt needs to be fed behind the tensioner arm. I managed to swap over the idler pulley by freeing off the secondary air solenoid but, even with the oil filter removed, I simply could not gain sufficient access to be totally confident that if I pulled out the old belt, which was visually in perfect condition, I would be able to feed through the new belt.

I decided that the only way to be 100% confident about the belt swap would be to remove the radiator fan and cowling. My first thought was that this cowling plus fan could be removed downwards as the front main crossbeam clearly prevented upwards removal. However, once I had freed off all the cowling fasteners and cabling, I could see that there is a plastic valve block or something bolted to the inside righthand side of the cowling which would make downwards removal impossible. As this block is so inaccessible, I decided that perhaps upward extraction was the way forward. I was also beginning to have doubts about whether the fan/cowling structure would actually clear the lower crossmember.

I then removed the main upper crossbeam but could then see that upwards extraction was also going to be hindered by the way the cowing is positioned under the radiator. Unless I'm missing something, It looks as if the radiator/cowling/fan assembly needs to be removed as a complete unit but this would involve draining down the cooling system and because I was now under some time pressure, I decided to leave the old belt in place and bolt everything back together. It should be said that access to the belt routing over the top of the water pump, where I had already pulled off the old belt, is also very poor so removing the upper crossbeam was actually helpful in refitting the original belt.

I have no doubt that it would be possible to remove and refit the belt without major disassembly but, assuming that I do want the best possible access, here are the questions:

1) Is it actually possible to remove the fan/cowing assembly without removing any of the radiator assembly? If so, it clearly involves unbolting of that righthand-side relay but does the fan/cowling assembly then come out downwards or upwards (the latter obviously involving removal of the front upper crossbeam)?

2) If the fan cowling assembly has to be removed along with the entire radiator assembly, that will clearly involve disconnecting the cooling hoses. However, does it also involve removing any oil cooler pipework, and most importantly, does the a/c condenser also have to come out as part of the assembly? If so, that is a deal breaker as I don't have any R134A containment equipment.

Any helpful observations will be gratefully received.

Richard

 

The workshop manual is listed in the stickies, above.
The manual clearly lays out the process you need to follow… BUT there is no need to disassemble the entire front end to change the belt!

 

Many thanks Guy.
I have the manual but I couldn't see where it spelled out whether you can remove the fan/cowling assembly as a unit. It is often the case that such things are possible even though the manual might suggest a process involving a lot more dismantling. Mechanics have often worked out a quicker/simpler method than the manual and hence my two specific questions.

I agree that the belt could be changed without removing the fan/cowling but it would make it a whole lot easier if the fan/cowling could be slid out as with the XK8. I agree that major dismantling of the front end would be a bridge too far just for the belt and I'll wait until I need to replace the water pump or whatever as well.

Richard

 

As guy said no need to dismantle the front end to replace a drive belt however to answer your question the fan/fan shroud can be removed whilst the radiator/condenser, X brace & PS cooler can all stay


Radiator, condenser, x brace and PS cooler removed as a total unit . Fan shroud came off first seperatly along with top lock

 

Thanks Steve.

The photo appears to show the plastic fan and shroud attached to the far side of the radiator but I don't have the car here to compare it.

Do you mean that the fan and shroud were first removed separately from the rad/condenser assembly prior to them being re-joined together for the photo? If so, does the fan and shroud remove upwards or downwards whilst leaving the radiator/condenser assembly in place? Removing it upwards will obviously require removal of the structural front crossbeam but that's easy enough. Is that main structural crossbeam what you refer to as the "top lock"?

The manual suggests that the assembly in the photo has to be removed as a complete unit so I'm pleased to hear that this is not the case.

Is that black cross-brace in the photo the one which is bolted to the engine-side of the fan/shroud assembly or is there a second cross-brace on the condenser side?

Richard

 

I finally found a YouTube video showing a similar job being undertaken on an X150 XKR but the job appears to be much simpler because, even though the supercharger belt is in the way and has to be slipped off to give access to the accessory drive belt, access to the top of the engine/water pump is then better than the XK and, crucially, the XKR appears not have the secondary air injection pipework running right in front of the drive belt close to the pulleys and it is this pipework which raises the belt change to whole different level on the XK compared to the XK8. ☹

Removing the secondary air injection pipework is also not a viable option as, according to the manual, that requires lifting the engine!

I'm surprised that I can't seem to find more information about whether, and how, the fan/shroud assembly can be removed as a unit but I might have another go at it later in the year if the chirping returns. For the time being, the belt is in perfect condition and a spray of belt dressing on the smooth surface has cured the chirping. Simply cleaning the belt with alcohol silenced it for a few hours but it then returned.

Richard

 

Also interested, since I'm at 80K and considering replacing the belt and tensioners as PM. 07 XK NA

 

It has been a minute, but I remembered the accessory belt being a very simple deal. Of course, I was 'in there anyway', so I went to the service manual to refresh my memory. It tells you:
1. Disconnect battery
2. Raise vehicle
3. Remove engine cover
4. Remove the air deflector
5. Remove the air intake duct
6. Release the accessory drive belt
7. Note fitted position
This is for the XK. No cooling components need to be removed.

 

As I said "I have no doubt that it would be possible to remove and refit the belt without major disassembly" but removal and replacement on the XK is certainly not easy like the XK8 unless you have stick-thin arms and tiny hands. The XKR appears to be much easier as the secondary air injection system pipework does not complicate matters. Removal of the oil filter is the single most effective way to improve access from below but removal of the cooling fan and housing, also a 5 minute job on the XK8, would make the job almost as simple as the XK8.

Richard

 

Just to update this thread, I had the XK up on the lift for the last couple of days to do some other work so I decided to have another go at replacing the accessory drive belt.

As I postulated above, the bottom line is that replacement of the belt is possible by removing only the intake ducting and, unless you have the tiniest hands and thinnest arms in history, by also removing the oil filter. This time, I did not remove the front crossmember this time as it is not necessary. The one gotcha that you have to watch for is that there is a small coolant hose right above waterpump pulley and on my car the clip which holds the hose onto the spigot was positioned so that there was insufficient clearance to slide the belt off the top of the pulley. Once the clip was loosened and move around a little the belt could be removed.

Having said all that, actually routing the new belt correctly is a nightmare operation and, by far, the hardest serpentine belt replacement I have ever undertaken. If you are a pinhole surgeon by training you will probably enjoy the challenge but otherwise be prepared for a frustrating couple of hours.

Richard

 

Fyi, Ive had the chirp before. And it was the alternator bearings. It all started when I decided to drive spiritedly. Old alternators in these cars do not like high RPMs when dropping down a gear or two. Anyway I had my Indy replace the alternator with a rebuild and the same thing happened, we then got a rebuild replacement and the same thing happened. Got a brand new AC Delco, and never had the problem again. If it does happen again I have found a shop that can rebuild them with abuse in mind. I think that factory new is the way to go since the alternators are built to withstand the abuse, mass rebuilt ones havent gotten it right yet.

 

In my case it was definitely the belt chirping on one of the pulleys as when I touched a piece of cloth dampened with spirit against the smooth side of the belt whilst it was chirping the chirp would stop immediately until the spirit dried out. I hoped that replacing the factory idler pulley with the modified ridged design as detailed in the Jaguar technical bulletin would fix it but it did not. The new belt is on now but I haven't tested it yet as I was changing the diff oil and brake pads yesterday.

I agree that alternator bearings, and other pulley bearings, are a common source of chirping / squealing and have changed many such bearings in the past.

Richard

 

Having now taken a test drive, the good news is that the belt chirping has now gone. Let's hope that it's a permanent cure.

Out of interest, the belt I have fitted is the Gates 6PK2315 which has a rough, textured finish rather than the OE Jaguar fitment, which I believe is a Dayco belt, and which has a smoother surface finish. Hopefully the textured finish will be less prone to chirping due to slight side-slipping on the smooth tensioner and idler pulleys as the belt spins.

Richard

 

"...Having said all that, actually routing the new belt correctly is a nightmare operation and, by far, the hardest serpentine belt replacement I have ever undertaken. If you are a pinhole surgeon by training you will probably enjoy the challenge but otherwise be prepared for a frustrating couple of hours."

Amen to that belt routing. It's the longest serp belt I've ever dealt with, and gets in the way of itself while feeding it. To help me, I copied the routing diagram from the service manual and flipped the image ("mirror" effect) on a copier. Since I was predominantly working from the rear of the engine, facing forward, this scheme helped this aging brain with the proper feeding of the belt around all the pulleys / idlers.

 

That's an interesting idea and one I've never heard of before.

In case it helps anyone else, I'll describe how I managed to overcome the issue of the secondary air injection system pipework running across the front of the pulleys.

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.

Richard