Evening all!

I've now done 2,700 miles in my old XJ6 (1994 3.2 litre). Jobs completed so far on this rather unloved car:

Oil and filter change
Rear shocks
Front pads
Air filter

In the last 300 miles a sqealing noise appeared. Chirping at first then eventually becoming a prominent squeal that would continue when pulling onto motorways up to 100kpmh sometimes. Certainly alarming enough not to be ignored!!

When I inspected the belts, the grooved sides of both were cracked and the one that runs the alternator and waterpump was actually starting to delaminate on the flat side so obviously neglected for some time.

Heres the procedure I used:

For a/c belt (which you have to remove first) jack up the car, place an axle stand of course. Working underneath the front loosen the 10mm bolt on the tensioner pulley. You'll see a threaded bar sticking down from the tensioner assembly. You tighten this to pull the pulley down. It has a square end and I used an adjustable spanner on it although I think a 1/2 inch imperial socket could fit this or mole grips. Its a bit fiddly but after a few turns you can actually do it by hand. Slip that belt off

Working from above in the alternator area, loosen the 14mm bolt on the bar/arm that holds the alternator in place at the correct angle. I used a deep 14mm socket to reach it although you could use a normal one with 6 inch extension bar. From the top you can see a clamp on a threaded bar. There is a nut either side of the clamp to hold it in position. I found that a 14mm spanner didn't seem to fit although a 15mm seemed a bit loose but anyway the latter worked. Loosen the lower nut first and wind it back about 2 inches. Then turn the top nut clockwise which will rotate the alternator and remove tension from the belt. Its a bit tricky working on the bottom nut as the more you undo it the more difficult it is to get a spanner on it. Eventually you'll be able to remove the belt. Slip new belt on. By hand turn the top nut back to more or less its original possition (you'll see where it was due to dirt!! Or in my case I did ....). Then wind back up the bottom nut. Check tension on the belt which I used the old method or turning it 90 degrees and when I find this offered quite some resistance left it that. Tighten down top nut. Retighten the bolt holding the arm/bar in place.

Back under the car loop the belt around the crank pulley and a/c compressor. Carefully pull down the remaining belt so it fits underneath the tensioner wheel. Turn the square end of the threaded bar anticlockwise until tight and so that the belt can just be twisted 90 degrees. Then tighten the 10mm bolt on the idler pulley.

Drink a beer and enjoy silent belts whirring around!!

Tomorrow rear pads and more investigation into the annoying rattling from the rear end.

Thats all folks!

Sam.

 

There are some problems with the alternator belt being too long by 10 cm

This depends on the manufacture and source

I would be guessing to remember my measurement on the size of the official Jaguar stamped part # belt on M' Lady P , but I believe it was 937 cm on the O. D.

I have read from others there are other non belt size related issues like the bearing freezing up on the alternator and the shelf life of the belt from the store being old and hard and the belt not having belt / pulley grip

There is also the case of the engine block pulley ( harmonic balancer ) delaminate and spinning hence no alternator turning ( easy test developed by someone else more experienced then I )

 

Thanks for your reply. I actually had problems ordering these in Spain. The description from Autodoc and Mister Auto both described cars from XYZ date (which excluded mine) and then for the other type until chassis number XXYYZZ which also excluded mine!! So I went for the latter. The alternator belt was a small amount longer because I had the wind the tensioner on the alternator back slightly more than where it started. However I am talking a few threads. Perhaps that equates to 10mm on the belt I don't know. When I took each off and offered the new one up against it they looked the same so I was relieved!!

 

The problem I have read from others on too long a alternator belt is the slippage no allowing the alternator to turn

This also relates to how old the belt shelf life is coming from the store in it's grip

There have also been problems with the alternator bearing freezing up

Back to your A/C tensioner

My long adjustment bolt was very stuck and I backed away from it before damaging the 4 point tool end

The car will run fine without the A / C belt while working it out

 

My AC belt tentioner was very stuck and this is how I resolved it

The car will run fine without this belt during repair

Mine was so stuck I was starting to round the 4 point square tool head with different tools so stopped before ruining the 4 points

I think I rolled the belt off but then removed the whole bracket to take over to a off car bench

Tensioner pulley carrier post is item # 1 and is what gets stuck

Wire brush the exposed heavy rust on the long adjustment bolt threads

By applying heavy heat to the carrier post with penetrating oil was able to work it back and forth which grinds out and cleans out the interior threads

keep running the carrier along the whole adjuster length as this cleans out the interior threads

If I remember the bolt # 4 must be loose in order for the pulley not to be pinched in place on the bracket and not adjust up and down

Finish by applying heavy grease to the long adjustment bolt exposed threads and other items and maybe in the future it will not be stuck

The sealed bearing pulley is a source of squeals and is cheap and substituted by others like GatesEditing

 

Well done, and that A/C adjuster is a mongrel at first.

None of my X300 had that plastic under tray, so access was simpler.

The aftermarket parts industry (where I have worked for 55 years), lists a 5PK0980 belt for the Alternator, and I found it TOO long, which put the alternator pulley WAY too close to the lower radiator hose.

I went with a 5PK0970 and even allowing for "wear stretch" it will never touch that hose.

 

Sorry to hear your adjuster is stuck. I guess I was lucky as a few turns with an adjustable spanner and I could turn it by hand. On the diagram I see there is a nut just above the square end on the adjuster but I don't recall seeing that on my car. If you car has that nut you could use a deep socket to get onto that and try turning it back and forth with some penetrating oil on the block at the top?

Ironically the a/c doesn't work on my car!!! So I could have left the belt off but I do plan to have it regassed very soon given its mid 30's here on a good day!!

 

My tensioner for the AC belt was almost impossibly stuck and have some tips for others that may have the situation

I had wrote it out in the Pic post above but disappeared so editing it back on that post