So i am looking to replace my alternator belt and figured whilst i was there i will replace the a/c belt and pulley.

now when looking for parts i find the official jag part number easy enough.
Alternator Belt - EBC11306
A/C Belt - EBC11220
Idler Pulley - NBC5012AA

When i look up parts for the car on dayco it tells me
Alternator - Belt Dayco - 5PK0980
A/C Belt - Dayco - 4PK1035
Idler Pulley - Dayco - 89017

however when i watched a video of someone doing the belts they have noted the belt used for the ac as
A/C Belt - Dayco - 4PK1010

i was just wanting to confirm before i buy them and potentially get the wrong belt.

I have the official Jaguar marked belts on mine and measured them for an alternate that would work

Off the top of my head 295 cm outside diameter and the difference between alternator and A / C compressor belts is 3 and 5 ribbed , the 2 belts are the same outside diameter

The idler pully is a common X brand , there is some tricks to getting it off

The alternator belt is critical as in reality it has little tension adjustment even with long adjustment bolt thread length

mmm... interesting you say the ac belt is 3 ribbed. both numbers i have come across for the ac belt indicate 4 ribs. will check that.

*edit
just checked the ac belt is 4 ribs.

also just saw on my parts car it has had altenator belt replacement with dayco 5pk0990
so again a different number.

G'day Spud,

The attached page is from the Jag parts catalogue.

Cheers,
Jeff.

So that confirms the proper jag part numbers.
now to see if i can properly match them to dayco or gates alternatives.
i think that is cheaper than trying to get them from somewhere like jagdaim.

i know they want $55 for the pulley and i can get the dayco alternative for about $25 elsewhere

Here's a couple of links to an ebay UK seller for the 2 belts.

I'm not saying this is definitive, but I use this seller for all my parts (for lots of cars that I look after) as their cross reference information is by far the best I have found. Not had a wrong part from them in last 5 years.


https://www.ebay.co.uk/itm/235553098...3ABFBMpMmA9vNj


https://www.ebay.co.uk/itm/235486357...3ABFBM4Ibj9fNj


HTH

thanks for that.
it lists the AC belt as 978mm long.
and lists the altenator belts as interchangeable with 5pk975 and 5pk980. (obviously suppliers like dayco use the length as the part number which makes it easier)
but lists the AC belt as 1020mm long and interchangeable with 4pk1019, 1020, 1021.
interesting then i have seen the two sizes referenced as 1010 or 1035.
i have seen belts listed as direct replacments for ebc11306 as 1035mm
maybe there is a decent amount of room for tension and adjustment on the AC belt.

just saw there is dayco ebc11306-g OEM replacement and it is a 4pk1025

It is indeed interesting to know that some suppliers go by the same parts number with different belt length. I just did an inventory check on various belts which I bought twice or more in the past few months trying to track down an irritating rattling noise from the pulleys and idlers.

Belt / Jaguar Parts Number / Size / Manufacturer
Drive Belt NBD7740BA 7BK1180 Dayco
A/C Belt EBC11120 4PK1020 Gates
A/C Belt EBC11220 4PK1013 Dayco
Alternator Belt EBC11306 5PK975 Dayco

Please note that, XJR fitted with a larger Lower Supercharger Pulley will have tighter space in the belt area and hence will need a shorter A/C Belt and Alternator Belt to avoid rubbing. In my case, I found that the following brands have shorter ones that worked:
AC Belt 4PK1013 (Dayco) or 4PK1015 (Mitsubishi)
Alternator Belt 5PK965 (Bando or Mitsubishi)