I've seen some power steering caps (P/N 7834183) have a rubber sleeve on the the dip stick, but I've seen others (including the one on my car) that don't have it. Would seem to help prevent splash of the fluid up on the cap.
Is it helpful to have this rubber sleeve?
Ya know, I didn't see this until just now. Only nearly 11 months ago, but hey, better late than never.
The rubber disc is an afterthought and an addition to the cap seal itself. OEM factory units did not have this rubber disc. It won't hurt to have it though, and nobody sees it unless they check your fluid level for you. The disc is there just as you said for splashup. Apparently it's one of those things where GM got enough complaints about fluid getting past the cap seal and dribbling out and all over the place on the power steering pump and getting blown all over the engine compartment and exhaust manifolds, etc. Not acceptable. So I imagine this was the cheap "fix" to keep the complaints and leaks down. I don't know when it occurred, but I'll bet there's a service bulletin out on that subject somewhere.
