Look for signs of that oily residue on the underside of the hood. If you see it there, it is likely oil vapors being slung up there by the pulley, then it condenses there. You will find that all over the entire engine after a few hundred thousand miles. If you only see the residue on the part, and it is on top and bottom of that part, it is a good suspect for a leak. If oil is being flung up there, you will not see as much on top. You can also wash the area, then wrap a piece of light cardboard around it and clamp it on the ends with tape. The goal is simply to shield it from oil spraying from other places. If you find oil residue on the cardboard, it's spraying from somewhere else. If it stays dry, but when removed, you find the same residue on the hose, suspect it is leaking at a connection in that area. A clear plastic bag, like a Zip Lock bag torn open, can work too.
To be leaking bad enough to leave oil, you should be able to verify it by mixing up a little dish soap with water, then wiping that on the joints. Watch for bubbles forming that indicate the location of a leak.
Friday, June 23rd, 2017 AT 2:21 PM