I have a xk8 x100 that has developed a noise when the aircon is switched off, if i put the aircon on noise goes away. Also when i kick it down and push it a bit the same noise appears. With the bonnet up it sounds like it is coming from the front of the engine. Any suggestions would be great fully received Thanks

 

Standard answer is to release the tensioner and remove the accessory belt. Make sure you have a diagram or even a picture to make sure you can put it back the way it is supposed to be. Then, rotate every pulley by hand and figure out which one is noisy or rough or somehow "not like the others". There is an idler (simple pulley on a bearing) and a tensioner (pulley on a spring) that can be replaced easily and are not terribly expensive. Obviously, focus on the A/C compressor. There is typically a fixed pulley on a bearing that always rotate with the belt. Then there is a clutch (a magnet, really) that can bring a plate in contact with the pulley to engage the compressor. All of that can wear out and make noise.

Other possibility is a slipping belt. There is typically some contamination (like cooling fluid dripping from somewhere) and the belt can slip under load. These belts are meant to work on dry surfaces.

 

+1 on fmertz suggestion. It would be most helpful if you had you vehicle information in your signature. If the tensioner pulley is bad Jaguar only sells the full tensioner assembly. Quite pricey!
Up to a certain year you can unbolt and replace the pulley since it is the same pulley as the idler pulley.

 

Welcome to the forum jyates37,

Good advice already given.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham