Could the change be something to do with removing the CFC's, which would have probably happened in the early 90's??
Personally I find WD 40 useful for getting water out of place it should not be, like improperly sealed HT leads or dizzy caps, works effectively at making old bangers start on damp days (grew up with many an old banger), its also OK as a light anti corrosion agent.
Never use as a lubricant, its dreadful at that, works OK as a penetrating oil when plus gas is not available.
Think it took so long to finalise as its a jack of all trades, master of none, fluid.
Whilst on the subject of fluids, anyone used this before
http://www.startyabastard.com/ the name caught my eye, very amusing.
Gone to the dark side.
Past Citroens
'99 Xantia HDi Exclusive
'99 Xantia 3.0 V6 Exclusive (Green Goblin)
'02 C5 Hdi 110 LX Estate
'98 Xantia 1.8 sx auto with LPG
'00 Xantia Hdi (110) forte
'97 Xantia 1.9D sx
'93 Xantia 1.9D lx (my first) R.I.P