In trying to track down the course of the oil stain on the ground inside the rear passenger wheel area every time I park the car, I looked at the oil fill/dipstick/radiator fill cluster in the rear trunk. I looked there because in searching in vain for the source of the oil leak, it appeared to me that the rubber hose that extends toward the ground in the area of the rear passenger tire had oil residue inside it, and a remain of a drip from it. I assumed this was the drain hose for the rear top well drain on the passenger side. In looking at the cluster in the trunk, the plastic trim plate that forms sort of a "floor" to the well they sit in was shiny with what appeared to be oil residue. The area around the dipstick was absolutely dry. Most of the residue seemed to be around the radiator fill cap. I cracked the cap open, and oil ooozed out - plenty of oil! This was followed by a seemingly unlimited amount of golden tan gooey water.
Not good. Damn, this sucks.
Does this dipstick/fill cap well area in the trunk drain out through this rubber hose as well? If so I have found the source of my oil leak. In searching, it seems that while there could be numerous sources of this oil in the water, the most common one is the water to oil cooler. I'll search for a good write up on the procedure, but this seems to be the easiest and most cost effective place to start.
It seems in my initial reading on the subject that the oil cooler itself is not terribly difficult to change, but cleaning the goo out of the cooling system is mind-numbingly monotonous. What's the best way to do this? What's the best method to drain the entire cooling system - where do I best open it to drain most of the junk that's in there? My thought is to completely drain it, and then change the oil cooler. Then I'll fill the cooling system with fresh water and the Prestone flush chemical (anyone know what it's called?). I'll run that to bring it up to temp, and then drain it. I'll use the chemical and fresh water again, bring it up to temp again and drain it. I'll fill with fresh water and chemical, and run it a day or so driving, Drain it again. I'll keep doing that with fresh water and chemical until such time it runs clean finally. I'll use chemical and fresh water each time.
If any of you have actually done this job and can offer any tips, or if any of you have any advice at all on changing the cooler, sourcing the cooler, flushing the system or anything else, please chime in here. It's terrifying to know that it could be something worse. I am strongly hoping that this is it.
For what it's worth, the engine oil is up to level and looks perfect. Once I am done I'll change it anyway. The car has run perfectly at 180 degrees. No overheating. All this started with looking for the source of the leak on the ground. See the other thread I started on this.
Hard to locate this oil leak
When I cracked the radiator cap open, pure oil initially oozed out. If the dipstick/fill cap well is connected to that drain hose, this has to be the source of my leak, at least I'm hoping it is. The car is a 2002 Boxster S.
Any help or input on this is greatly appreciated.