My heating fan(s?) have recently become very noisy - seemingly from the passenger side (it's a RHD drive UK spec XJR6). The sound gets louder or quieter depending on the fan's speed of operation: faster and louder; slower and quieter.

Has anyone experienced this and does anyone have any thoughts about repairing/curing the problem?

Apologies for lack of information but without taking the dash off I can't really say much more!

 

There are reports of insulation or something migrating down into the cage on X308's . Don't know if this applies to the X300's

Have you isolated it down between left and right side by pulling fuse X and Y ?