what kinda of oil used for power steering on E4?! is it dexron 1/2/3, mercon 1/2/3 or those off-the-shelf power steering fluid of any make?! seems light reddish in color but at the MIN level on cold check this morning, kinda worried tho'. not sure what oil is currently used but can i top it using other kinda oil without flushing out the existing one, is this ok/normal?!