Pushing down on that hose will not affect the oil return hose below the oil separator. I have all that stuff off my 81 right now. Taking the oil separator off the block exposes a ledge on the side of the block where the oil separator sits when installed, held firmly by two bolts. On the ledge on the side of the block, there are two holes, both covered by the separator when it's installed. The rear hole is about one and one-half inches in diameter. Oil vapors from the crankcase come up this hole into the oil separator. The front hole is smaller, about three quarters of an inch in diameter. The oil separator separates the oil from the vapors, and lets oil flow back into the crankcase down a hose which is pretty firmly mounted in this forward hole. My separator came off easily without disturbing the oil return hose at all. The oil separator should be firmly mounted on the ledge I described. If it is not loose, (It would be a pretty freak thing for yours to be loose) there is no way pushing on the flame trap hose will bother the oil return hose below the separator. Grab the top nipple of the separator, where the flame trap hose attaches, and try to wiggle it. It probably won't budge, which is good. BTW, the separator on my car is plastic. Hope this helps. DougC