I would never use WD40 as a permanent lubricant. If there's a pulley squeaking or stiffening, it needs to be replaced.
My 94 LS400 I bought a month ago, just broke the drive belt. Feeling the pulleys, I found that the fan clutch brackt pulley had froze up solid. Didn't have any warning either. Find out which pulley is squealing before you break down and have to wait for parts. (I am a new member and this is my first reply, hope I didn't pull a fopah of any sort)
I own a 94 ls 400 , wife said it was knocking , checked all the pulleys , after checking the belt, & the pulley was not harmonic. It looks to be the bearings on the bearing bracket(I thought it was the water pump!), my mech. said the part is around $100, but the labor is quite a bit, because you have to disassemble the same components as you would if you are changing the timing belt, so you might as well replace timing belt if it's old. I'll elaborate on the job & the price in a cpl days , thanks !
