XK8 throws the drive belt

[MDCanaday]

I have had an odd noise coming from the drive belt since we got our cat last year,mostly when cold.Last week, I got out the WD40 and gave it one little spritz,which instantly shut it up.Turned around to put the can away,and the serpentine belt slithered onto the drive!!Through inspection of all the pulleys and tensioner yielded no faulty parts.The belt looks new also.After getting a diagram of the proper routing, the belt went on easily and now makes no sound.What in the heck was the problem???Has anybody ever had any similar problem with this drive belt???
MD(mad dog)

 

[vettedog72]

Just a guess: bad belt, missrouted or both? I bet on the bad belt since your replacement has no problems.

 

[MDCanaday]

I re-used the belt as it was OE and had no defect to be found.I can only presume that the Mechanic that installed it(before we owned it)did not get the belt completely over the AC pulley.We have now driven it for 300 miles with no noise and no problems. The car is a doll on the road,and is other wise good, if you can ignore the leaking cam cover(smokes).....
MD(mad dog)

 

[Silverghost]

Just an off hand guess but if the belt was a touch loose or the tensioner not set properly, the belt may have been slipping slightly and riding up on one of the pulleys. When you hit it with the WD40, it was able to ride all the way up, over and out......??

 

[Exotexs]

typical XK8 problem, thousands report the same all over the world. Ford block.
Not a real Jaguar engine.